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In the conversion process of syngas-to-C2 species, the OH species are inevitably produced accompanying the production of key intermediates CHx(x = 1–3), traditionally, the function of surface OH species is generally accepted as the hydrogenating reactive species. This work for the first time proposed and confirmed the assisted catalytic mechanism of surface OH species that performed as the promoter for syngas-to-C2 species on Cu-based catalysts. DFT and microkinetic modeling results reveal that the produced OH species accompanying the intermediates CHx production on the MCu (M = Co, Fe, Rh) catalysts can stably exist to form OH/MCu catalysts, on which the presence of surface OH species as the promoter not only presented better activity and selectivity toward CHx(x = 1–3) compared to MCu catalysts, but also significantly suppressed CH3OH production, providing enough CHx sources to favor the production of C2 hydrocarbons and oxygenates. Correspondingly, the electronic properties analysis revealed the essential relationship between the electronic feature of OH/MCu catalysts and catalytic performance, attributing to the unique electronic micro−environment of the catalysts under the interaction of surface OH species. This new mechanism is called as OH-assisted catalytic mechanism, which may be applied in the reaction systems related to the generation of OH species.

The phenomena that results on supramolecular aggregations of bimetallic[Pt2L4] and [AuL2] are reviewed. Supramolecular [AuL2]n (n = 2,3) wereobserved in some cases in solution as a result of Au(I)···Au(I) aurophilicinteractions, which also direct the assembly of oligomeric structures in crys-tal phase. Analogously, Pt(II)···Pt(II) attraction accounts for the assembly of[Pt2L4]nsupramolecules which can result on 1D semiconductive arrangementsin crystal phase and direct the formation of 1D nanofibres on surfaces. Finally,oxidation of [Pt2L4] to [Pt2L4I]n produces highly conductive polymers thatcan reversibly assemble/disassemble into [Pt2L4] and [Pt2L4I2]. Such out-standing ability results on an unprecedented processability that enables MMXpolymers for technological applications as molecular wires.

Hydrogen energy has long been recognized as a clean alternative to conventional fossil fuels, which can be applied in a wide range of transportation and power generation applications. The rational design and engineering of high-performance and robust catalysts for hydrogen evolution reaction (HER) shows not a great significance but a challenge for efficient electrochemical water splitting. Herein, a new type of Ni-based Ni-ABDC precursor has been obtained, which leads to the formation of N-doped porous carbon nanomaterials uniformly coated with well-proportioned bimetallic AgNi alloys via a stepwise strategy. To their credit, all samples of AgNi/NC-X are structurally calcined from the pristine AgNi-ABDC-X by tuning the different concentration of AgNO3, which means all of them maintain the vermicelli-like morphology compared with Ni-ABDC. The series of AgNi/NC-X materials can be regarded as effective electrocatalysts for HER both in acidic and alkaline media, but an acid-leaching phenomenon is observed. Among them, the as-prepared AgNi/NC-2 exhibits a low overpotential of 103 mV at the current density of 10 mA cm−2 and decent durability with a high retention rate of 90.9% after 10 h in 1.0 M KOH electrolyte. The compelling HER properties of AgNi/NC-2 can be attributed to the synergistic effect between the hierarchical carbon materials, partial N-doping and abundant AgNi alloys. Meanwhile, this study provides a practicable method for the development of efficient HER electrocatalysts for energy applications, which can be conveniently prepared through the reasonable introduction of active components in the crystalline inorganic-organic precursors.

A series of CoPd/KIT-6 bimetallic catalysts with various Co:Pd molar ratios at different calcination temperatures were prepared and used for the direct synthesis of H2O2 from H2 and O2. These catalysts were characterized by nitrogen adsorption-desorption, low and wide-angle X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), scanning electron microscopy (SEM), elemental mapping and energy-dispersive X-ray (EDX) methods. It was found that the particle size, electronic interactions, morphology, and textural properties of these catalysts as well as their catalytic activity in the reaction of H2 with O2 were affected by Co addition and different calcination temperatures. Also, the results showed that while the H2O2 selectivity depends on Pd2+ species, the H2 conversion is related to Pd0 active sites. Among these catalysts, CoPd/KIT-6 calcined at 350 °C (CoPd/KIT-350 catalyst) showed the best catalytic activity with 50 % of H2O2 selectivity and 51 % conversion of H2.

Improving catalytic performance is a yet still challenge in thermal catalytic oxidation. Herein, uniform mesoporous MnO2 nanosphere-supported bimetallic Pt–Pd nanoparticles were successfully fabricated via a SiO2 template strategy for the total catalytic degradation of volatile organic compounds at low temperature. The introduction of mesopores into the MnO2 support induces a large specific surface area and pore size, thus providing numerous accessible active sites and enhanced diffusion properties. Moreover, the addition of a secondary noble metal can adjust the Oads/Olatt molar ratios, resulting in high catalytic activity. Among them, the catalyst having a Pt/Pd molar ratio of 7:3 exhibits optimized catalytic activity at a weight hourly space velocity of 36,000 ml g−1 h−1, reaching 100% toluene oxidation at 175 °C with a lower activation energy (57.0 kJ mol−1) than the corresponding monometallic Pt or non-Pt-based catalysts (93.8 kJ mol−1 and 214.2 kJ mol−1). Our findings demonstrate that the uniform mesoporous MnO2 nanosphere-supported bimetallic Pt–Pd nanoparticles catalyst is an effective candidate for application in elimination of toluene.

Ru and Mo bimetallic catalysts supported on active carbon modified by Phosphotungstic acid (PW) were designed and applied in glycerol hydrogenolysis reaction. The physicochemical properties of the catalysts were characterized and the presence of active sites was investigated from the perspective of the glycerol hydrogenolysis performance. The MoOx is highly selective for the C-O bond cleavage of glycerol molecules, which can reasonably regulate the strong C-C bond cleavage activity of Ru nanoparticles. By using sequential deposition of Ru and Mo supported on mesoporous PW-C, the characterization results show that the combination of isolated low-valence MoOx with metal Ru particles can form “MoOx-Ru-PW”, which provides highly catalytic activity toward C-O bond cleavage, selectively producing more C3 alcohols (mainly 1,2(3)-propanediol). The glycerol conversion of 1 % Mo/Ru/PW-C catalyst was 59.6 %, the selectivity of C3 alcohol was 96.1 %, and the selectivity of propanediol (1,2(3)-propanediol) was 94.9 %. It is noteworthy that the selectivity of 1,3-propanediol reached 20.7 % when the PW was 21.07 % (mass). This study provides experimental evidence for the tandem dehydration and hydrogenation mechanism of the multifunctional Mo/Ru/PW-C catalyst.

Bimetallic PtPd nanowires are produced by the centrifugal electrospinning method and their application as electrocatalysts in the cathode of a proton exchange membrane fuel cell (PEMFC) is evaluated. The effects of system parameters on the morphology of PtPd nanowires after calcination are explored including the rotation speed of spinneret, applied electric field, and atomic ratio of Pt and Pd in the composition. Cyclic voltammetry tests are conducted to characterize the electrochemical property and the produced PtPd nanowires are employed to fabricate the cathode catalyst layer in a PEMFC. The cell performance is measured and compared with commercial Pt/C electrocatalysts. Results show that bimetallic PtPd nanowires can be produced successfully with minimum mean diameter of 79 ± 24 nm and maximum electrochemical active surface area (ECSA) of 10.29 m 2 g − 1 at the atomic ratio Pt:Pd = 3:1. By the accelerated degradation tests, the PtPd nanowires demonstrate better durability than Pt/C. The present results reveal that the centrifugal electrospinning method can successfully fabricate PtPd nanowires which have great potential to be utilized in PEMFCs.

Designing highly active and selective metal nanocatalysts for use in liquid chemical hydrides is highly attractive but remains a critical challenge. Herein, bimetallic NiPt nanoparticles (NPs) immobilized on lanthanum oxycarbonate (NiPt/La2O2CO3) have been facilely synthesized via an alkali-assisted reduction method. The introduction of NaOH is the key factor to the formation of the well-dispersed and ultrafine NiPt NPs (2.8 nm). The obtained Ni0.6Pt0.4/La2O2CO3 exhibits an extraordinarily high catalytic activity and 100% H2 selectivity for hydrous hydrazine dehydrogenation, providing a turnover frequency value (TOF) high up to 490 h-1 at 298 K. Additionally, the NiPt/La2O2CO3 prepared with NaOH demonstrates higher catalytic performance and lower activation energy than that of NiPt/La2O2CO3_N prepared without NaOH. Moreover, the NiPt/La2O2CO3 also shows an outstanding catalytic efficiency (TOF = 1200 h-1) for dehydrogenation of hydrazine borane at 298 K. The efficient catalytic performance may be attributed to the small size effect, the strong metal-support interaction, and the NaOH promotion effect. This alkali-assisted reduction method provides a new perspective for preparing of highly efficient catalysts in clean energy application.

Assembling the reactive low-cost Co clusters and photoresponsive ligands in the form of metal–organic frameworks (MOFs) is a promising strategy to construct efficient water-oxidizing photocatalysts...

Selective hydrogenation of cinnamaldehyde (CAL) toward cinnamyl alcohol (COL) is an extremely important and challenging reaction. Herein, a series of PtxFey-Al2O3 bimetallic catalysts with varied Pt to Fe ratios were prepared by incipient wetness impregnation method. The introduction of Fe significantly modifies the electronic and surface properties of Pt, which clearly enhances the C=O hydrogenation selectivity. Among all the catalysts, Pt3Fe-Al2O3 displays the best catalytic performance and the conversion of CAL is 96.6% with 77.2% selectivity of COL within 1 h. In addition, Pt3Fe-Al2O3 had excellent reusability with 76% COL selectivity after five runs of the recycle process. Further characterization of the fresh, used and cycled catalysts revealed that the structure and electronic state of the synthesized PtxFey-Al2O3 are unchanged after hydrogenation reaction. The identical-location transmission electron microscopy (IL-TEM) results revealed that the interaction between the nanoparticles and the supports was strong and the catalyst was relatively stable.

The process parameters for dry reforming of methane (DRM) over Ni–W/Al2O3–MgO catalyst are optimized using response surface methodology (RSM). The Ni–W bimetallic catalyst is synthesized by co-precipitation method followed by impregnation. The catalysts are characterized by BET, XRD, FESEM, EDX and TEM; to study physicochemical properties, morphology, composition, crystallite size and deposited carbon. The effect of process parameters, i.e., reaction temperature (600oC–800 °C) and feed gas ratio (0.5–1.5) on the CH4, CO2 conversions and syngas ratio are studied. A temperature of 777.29 °C with CH4: CO2 of 1.11 at GHSV of 36,000 cm3gm.cat−1h−1, delivered the CH4 and CO2 conversions of 87.6% and 93.3%, respectively along with H2:CO of 1. The predicted process parameters were verified through actual experimental analysis at the optimized conditions, and results agreed with CCD of the RSM model with insignificant error. The MWCNT formed during DRM avoided catalyst deactivation and delivered stable performance over 12 h of reaction test at the optimized conditions.

CO methanation has arisen as an attractive research area due to its ability to transform syngas into substituted natural gas. Current monometallic catalysts have a severe problem; quickly deactivated. It is generally known that by introducing another metal to create a bimetallic catalyst, synergistic interaction between both metals considerably enhances catalyst effectiveness. This paper provides a detailed overview of bimetallic catalysts for CO methanation, covering its synthesis method and effect on physicochemical characteristics. The bimetallic catalyst can both reinforce or weaken the metal-support and metal-metal interaction, which weakening it favors reducibility while reinforcing it favors stability. Particle size and dispersion also improve, whereas adding lanthanides can increases the basicity. We also present the mechanism of CO methanation over the bimetallic catalyst, which modifies the mechanism's energy and rate value. This review provides insights on how reaction effectiveness is enhanced, enabling catalyst development with the highest possible performance.

Catalytic hydrothermal liquefaction of empty fruit bunch (EFB) with no added H2 effectively produces biomass derived fuel or known as bio-oil. In this study, a bimetallic modified zeolite (BaNi, BaLa and BaCe/CHZSM5) catalyst with a series of dosage ratio (1:1, 1:2 and 2:1) was used for the EFB conversion to bio-oil. Ni, La and Ce addition to the Ba/CHZSM5 showed significant changes on the physicochemical properties of catalysts and exhibited enhanced catalytic performance. The activity-structure correlation revealed that EFB conversion and bio-oil yield were favoured on bimetallic modified CHZSM5 and the most effective catalyst was Ba1La2/CHZSM5. Brunauer–Emmett–Teller (BET) surface area measurement and temperature programmed desorption of ammonia (TPD-NH3) results confirmed that high surface area and rich acidic sites of Ba1La2/CHZSM5 catalyst eventually enhanced the catalytic activity in HTL of EFB. Comparing to other bimetallic modified catalyst, the desirable aromatic and aliphatic hydrocarbon also predominated over Ba1La2/CHZSM5 catalysed reaction which demonstrated that this catalyst have a good ability in produce high quality of bio-oil with less oxygenated compounds.

A series of nine different mono and bimetallic catalysts based on Ni, Rh and Pd supported on γ-Al2O3 or CeO2-Al2O3 was screened and compared in terms of activity and stability for the dry reforming of methane (DRM) reaction. All catalysts were prepared by the incipient wetness impregnation (IWI) method and characterized by XRD, XRF, TPR, H2 chemisorption and N2 physisorption. The used techniques aimed at determining crystalline phases, metal loading and dispersion and textural properties, which are properties that will affect the catalytic performance. The reactions were carried out in a fixed bed quartz reactor with temperatures ranging from 700° to 800 °C, WHSV 30 L gcat−1 h−1 and CH4:CO2 = 1 for periods of at least 48 h. All monometallic Ni based catalyst suffered from deactivation by coke deposition in the first hours of reaction at 700 °C. However, the original catalytic performance of these catalysts was restored after a regeneration treatment. At higher temperatures (800 °C), the 15%Ni/CeO2-Al2O3 catalyst presented no obvious signs of deactivation over the course of 48 h. Monometallic Pd/CeO2-Al2O3 catalysts, despite presenting higher turnover frequencies (TOF) when compared to monometallic and bimetallic Ni based catalysts, lost activity due to coke deposition. Both monometallic Rh based catalysts (0.5%Rh/CeO2-Al2O3 and 1%Rh/CeO2-Al2O3) presented a remarkable activity and stability with no signs of deactivation for 96 h TOS. The 0.5%Rh/CeO2-Al2O3 catalyst presented the highest TOF values among all screened catalyst with TOFCH4 of 9.9 s−1 and TOFCO2 of 12 s−1.

This work presents the hydrothermal synthesis of Dandelion flower-like bimetallic oxide for the hydrodesulfurization (HDS) of dibenzothiophene (DBT). The synthesized oxide and respective activated catalysts were characterized by Fourier transform infrared- attenuated total reflectance (FTIR-ATR) spectroscopy, nitrogen physisorption, X-ray diffraction (XRD), Scanned electron microscopy-energy dispersive spectroscopy (SEM-EDS), high-resolution transmission electron microscopy (HR-TEM), and X-ray photoelectron spectroscopy (XPS). The oxide sample exhibited a flower-like core-shell structure (TEM) and suitable BET surface area for the intended application, (133.4 m2.g−1). The FTIR-ATR analysis confirmed the decomposition of the organic precursor in the synthesized catalyst. Two activation methods were followed for the oxide sample sulfidation, namely, in-situ high-pressure sulfidation and ex-situ low-pressure sulfidation. Also, the TEM micrographs of sulfided catalysts showed that the core-shell structure prevailed. The HDS of DBT activity results showed that catalyst sulfided under high-pressure resulted in enhanced activity, 2.4 times than the low-pressure sulfided catalyst, owing to the high degree of sulfidation (XPS) and the presence of short/curved MoS2 slabs (XRD & TEM). The activity of the df-NiMo catalyst was compared with the trimetallic NiYMo catalyst.

A series of Pt/CeO2 (5 wt%) and bimetallic Cu-Pt/CeO2 (4 wt% Cu and 1 wt%) catalysts supported on different CeO2 nano shapes (polyhedra, rods, and cubes) were studied as catalytic systems for hydrogen production from the methanol decomposition (MD) reaction. Supports were prepared by hydrothermal approach and the active phase was incorporated by wet impregnation. Materials were characterized by SEM, HRTEM-STEM, N2 adsorption, EDS, XRD, Raman spectroscopy, H2-TPR, and CO-DRIFTS. The catalytic properties for MD reaction were studied as a function of temperature in the 100–450 °C range and as a function of time on-stream for 24 h at 350 °C. Despite the high methanol conversion presented by the Pt/CeO2 catalysts, more important in polyhedra and rods, these catalysts exhibited a low hydrogen yield. Differences in the properties of bimetallic Cu-Pt/CeO2 samples were established to be support-morphology-dependent, and the dispersion of copper and the ceria reducibility were superior in samples supported on polyhedra and rods as in the case of platinum catalysts. An improvement of the oxygen vacancies in the bimetallic system was also observed, as a result of the close interaction between copper and ceria. TOF values indicated that catalytic performances are promoted not only by the size of the active phase nanoparticles, but also by the facet predominantly exposed by ceria. The formation of bimetallic phase and the presence of surface Cu-Pt alloy sites in the rod-shaped sample accounted for the slightly better methanol conversion in the stability tests. The H2 yield in the bimetallic samples was superior compared to platinum, which makes them suitable candidates for the hydrogen production from the methanol decomposition.

Iron, cobalt, and bimetallic catalysts were synthesized from their cationic solutions and impregnated on mesoporous silica support (i.e., SBA-15) to study their behavior in the catalytic hydrogenation of CO (Fischer-Tropsch Synthesis). N2 adsorption-desorption isotherms at 77 K showed that the mesoporous structure remained unchanged after the metal impregnation; however, the overall textural properties of impregnated materials decreased. SEM images did not show the presence of metal deposits on the support surface; however, both EDS and XRF analysis indicated the presence of iron and cobalt. Both XPS and TPR identified hematite and cobalt oxide as the main components in catalysts. In the Fischer-Tropsch Synthesis, the bimetallic catalysts presented higher activity than monometallic catalysts. The two bimetallic catalysts presented a decrease in methane selectivity and high production of gasoline and hydrocarbon chains larger than decane.

For the first time, the present work shows a combined theoretical and experimental analysis of the preferred adsorption sites for both methanol and methoxy species over Cu, Pt, and bimetallic Cu-Pt clusters - up to 5 atoms in size - supported on CeO2(111) as model systems. DFT+U calculations compared to methanol adsorption experiments followed by DRIFT spectroscopy over Cu, Pt, and bimetallic Cu-Pt nanoparticles supported over CeO2 octahedra, exposing only {111} crystal planes. From our DFT+U calculations, we found that methanol adsorption over the CuPt/CeO2(111) system is slightly favored, compared to the pristine CeO2(111) surface. Similarly, methoxy species formed through methanol dehydrogenation (CH3O- + H+) adsorb preferably over the metallic clusters, compared to the pristine oxide surface. This promotion is explained by the higher coordination of the methoxy species over the cluster, especially for those containing a higher amount of Cu atoms. This results highlights the oxidized Cu sites' role in the catalytic process, followed by the surface cerium atoms reduction of the support. The interaction of methanol with the substrate oxygen weakens the O-H bond, which results in a reduction in the energy barrier when the reaction occurs on the surface and interface, compared when this occurs exclusively on the metal cluster. However, after this step, the potential energy surface's depth suggests that methoxy species prefer to be adsorbed over the metal clusters. Experimentally, methanol was adsorbed over Cu, Pt, and bimetallic Cu-Pt nanoparticles supported over CeO2 {111}-octahedral particles. Through in-situ DRIFTS, bands related to adsorbed methanol and methoxy species were identified. A blue shift in all the bands was observed, related to metals’ influence in adsorbed species' vibrational mode. In the experimental spectra, new contributions in Cu-containing catalysts appeared, which were identified as adsorbed species over the metallic cluster and the interface, rationalized by calculated spectra.

Coordination polymers (CPs) have great potential to be used in electrocatalysis owing to their designable compositions and structures. It is highly challenging to apply CPs as electrocatalysts for oxygen evolution reaction (OER) on account of insufficient catalytic efficiency and relatively poor stability of current electrocatalysts. Herein, through a mixed-metal strategy, one-dimensional CoxNi1-x-HIPA with dual active sites was synthesized and studied for OER electrocatalysts. By changing the metal ratio of CoxNi1-x-HIPA, the OER performance was well regulated. The optimized Co1/2Ni1/2-HIPA exhibited minimum reaction activation energy, and represented an overpotential of 367 mV to reach 10 mA/cm2 at 25 °C. Moreover, an overpotential of 314 mV at 10 mA/cm2 was obtained from Co1/2Ni1/2-HIPA at 55 °C. This mixed-metal strategy provides a feasible way for adjusting the electronic states of the electrocatalysts to improve the electrocatalytic OER performance.

All-solid-state lithium batteries (ASSLBs), receiving extensive attentions and studies, exhibit better safety, environmental friendliness, stability, wider electrochemical stability window and higher energy density than traditionally liquid lithium batteries. In a variety of inorganic materials, with highly replaceable, the non-lithium metal elements emerge in endlessly and affect performances in diversiform ways. Due to facile preparation, convertible structures and excellent properties, the lithium-containing bimetallic granular materials are often applied as important components of electrolytes in lithium batteries. In this review, in terms of the properties of substituted elements, changing crystal structures, increasing vacancies or defects and improving the interfacial conductions, the roles of metal element substitutions of inorganic particles on the improvement of solid-state electrolytes are expounded. And the applications of substituted strategies in ASSLBs as the host of inorganic particles electrolytes and as fillers or modifications for composite electrolytes are also investigated and discussed. It also summarizes the current concerns and obstacles that need to be broken through, as well as provides a basis guide for the selection and optimization of inorganic particles.

The present research work discusses the influence of platinum nanoparticles on the catalytic activity of Cu/TiO2 catalysts for soot, formaldehyde, and carbon monoxide oxidation. The results showed that the size of the platinum nanoparticles, loaded on the Cu/TiO2 nanostructure, varied from 1 to 2 nm. The Pt-Cu/TiO2 catalyst exhibited effective catalytic performance in the oxidation of formaldehyde at 25 °C (99% of conversion), CO at 100 °C (90% of conversion) and soot at 300 °C (100% of conversion) due to the platinum particle size and Pt-Cu interaction, which developed Ti3+ and oxygen vacancies on TiO2. Moreover, the bimetallic catalyst consisted of a complex mixture of Cu2+, Cu1+, and Pt0 species. The Pt-Cu/TiO2 catalyst showed stability in the three different reactions from 20 to 300 °C.

Design and preparation of dual-role anode materials with extraordinary performance for rechargeable Li/Na-ion batteries (LIBs/NIBs) remains highly challenging. Herein, three-dimensional (3D) pomegranate-like porous bimetallic NiCo2Se4 spheres with N-doped carbon (termed as NC@NiCo2Se4) is synthesized by solvothermal method and annealing. Microstructure investigations reveal that the NC@NiCo2Se4 spheres include nano-sized NiCo2Se4 particles as inner core and NiCo2Se4 with the modification of thin-walled N-doped carbon layer as inner/outer shell. The bimetallic NC@NiCo2Se4 spheres possess synergistic interaction of Ni/Co atoms to enhance intrinsic conductivity and electrochemical activity, unique pomegranate-like structure with an inner void space and robust shell to mitigation volume expansion, and intimate contact of N-doped carbon layer to improve interface effect and accelerate conversion kinetics. As anode materials, the NC@NiCo2Se4 exhibits superior lithium/sodium storage performances (1401.6 and 794.8 mA h g−1 at current density of 0.5 and 5 A g−1 after 500 cycles for LIBs as well as 433.9 mA h g−1 at 3 A g−1 after 1000 cycles and a high capability of 306.6 mA h g−1 at 20 A g−1 for NIBs). This work represents an impressive strategy for future research of bimetallic selenides as anode materials for advanced high-performance LIBs/NIBs.

Reverse water gas shift (RWGS) reaction is a crucial process in CO2 utilization. Herein, Ni- and NiCe-containing hexagonal mesoporous silica (Ni-HMS and NiCe-HMS) catalysts were synthesized using an in-situ one-pot method and applied for RWGS reaction. At certain reaction temperatures 500-750 °C, Ni-HMS samples displayed a higher selectivity to the preferable CO than that of conventionally impregnated Ni/HMS catalyst. This could be originated from the smaller NiO nanoparticles over Ni-HMS catalyst. NiCe-HMS exhibited higher activity compared to Ni-HMS. The catalysts were characterized by means of TEM, XPS, XRD, H2-TPR, CO2-TPD, EPR and N2 adsorption-desortion technology. It was found that introduction of Ce created high concentration of oxygen vacancies, served as the active site for activating CO2. Also, this work analyzed the effect of the H2/CO2 molar ratio on the best NiCe-HMS. When reaction gas H2/CO2 molar ratio was 4 significantly decreased the selectivity to CO at low temperature, but triggered a higher CO2 conversion which is close to the equilibrium.

Recycling performance of heterogeneous catalysts is of crucial importance especially for a batch reaction system. In this work, we demonstrate a strategy for enhancing recycling performance of Ir-Re/SiO2 catalyst synergized with amberlyst-15 in glycerol hydrogenolysis to produce 1,3-propanediol. Comprehensive characterization results reveal that the Re sites in the Ir-Re/SiO2 catalyst undergo irreversible segregation and oxidation. These hinder the formation of active Re-OH species and thus contribute to a complete and irreversible deactivation. However, the introduction of amberlyst-15 into the reactant mixture can restrain the oxidation process of Re sites and favor the formation of Re-OH species, and thus significantly enhance the catalytic recycling performance. The results demonstrated here could guide the development of excellent bimetallic catalysts with the desirable recycling performances for the reaction.

Selective hydrogenation catalysts play a key role in many industrial processes, but they are primarily based on supported noble metals, such as Pt and Pd, which are usually dispersed in nanoparticles. However, the production and recovery of these noble metal nanoparticles is a very energy-consuming and expensive procedure. Accordingly, replacing these metals by other inexpensive, transition metals such as Fe and Cu without sacrificing the activity and selectivity, will necessarily reduce their production costs. Moreover, zeolites as a support provide the advantage of shape selectivity to the desired product. In this study, we develop an alternative method for preparing hydrogenation catalysts composed of metallic nanoparticles encapsulated into zeolite frameworks through reductive demetallation of Fe-zeolites or Cu/Fe-zeolites with MFI topology. Particularly, the process of reductive demetallation is described using temperature-programmed reduction (TPR) and Mossbauer spectroscopy data. The reductive demetallation of Fe-MFI, consisting of Fe extraction from the zeolite framework and formation of Fe0 nanoparticles, starts at the temperatures above 800 ℃ and finishes at 1030 ℃, when sintering occurs strongly. In contrast, introduction of second metal leads to the decrease in the reduction temperature, as process of CuFe@MFI formation finishes at 800 ℃. Both Fe@MFI and CuFe@MFI show activity in p-nitrotoluene hydrogenation to p-toluidine. Conversion of the substrate grows with increase in the Cu and Fe loading. Thus, this synthesis method of encapsulation of Fe0 nanoparticles and Fe0-Cu0 bimetallic nanoparticles into the zeolite micropores through reductive demetallation of Fe-zeolites can be used to prepare hydrogenation catalysts.

The organic compounds contaminated soil substantially threatens the growth of plants and food safety. In this study, we synthesis zero-valent bimetallic Fe/Cu catalysts for the degradation of 2,4-dichlorophenol (DCP) in soils with persulfate (PS) in combination of organic surfactants and exploring the main environmental impact factors. The kinetic experiments show that the wt5% dosage of Fe/Cu exhibits a higher degradation efficiency (86%) of DCP in soils, and the degradation efficiency of DCP increases with the increase of the initial PS concentration. Acidic conditions are favorable for the DCP degradation in soils. More importantly, the addition of Tween-80, and Triton-100 can obviously desorb DCP from the soil surface, which enhances the degradation efficiency of DCP in soils by Fe/Cu and PS reaction system. Furthermore, the Quenching experiments demonstrate that SO 4 ·- and ·OH are the predominant radicals for the degradation of DCP during the Fe/Cu and PS reaction system as well as non-radical also exist. The findings of this work provide an effective method for remediating DCP from soils. © 2020 The Chemical Industry and Engineering Society of China, and Chemical Industry Press Co., Ltd.. All rights reserved.

Supported NiCu bimetallic catalysts have been produced in-situ on commercial Al2O3 by using layered double hydroxides as precursors. The resulting catalysts show a uniform Ni and Cu distribution, thus providing good activity and selectivity in the reforming reaction of n-heptane. The catalytic performance has been found to depend on the Cu/Ni ratio, revealing the synergic catalysis between homogeneously dispersed Ni and Cu sites. The good catalysis of NiCu bimetallic catalysts makes it possible to partly or even completely replace Pt with NiCu bimetallic catalysts.

Core-shell structured Ni-ZIF-67@ZIF-8 derived bimetal selenides encapsulating into a 3D interpenetrating dual-carbon framework (Ni3Se4@CoSe2@C/CNTs) have been designed and prepared via carbonization and subsequent selenization processes. In this hierarchical structure, Ni3Se4@CoSe2 nanocrystals were uniformly dispersed into the 3D carbon framework structure/carbon nanotubes networks, which greatly enhanced the electronic conductivity and further enabled ultrafast Na-ion diffusion kinetics. When used as anode materials of sodium ion battery (SIB), The Ni3Se4@CoSe2@C/CNTs electrode delivered the excellent rate capability of 206 mA h g-1 at 3 A g-1 and marvelous cyclic stability with capacity retention of 243 mA h g-1 after 600 cycles at 1 A g-1. This research provides a new way to prepare bimetallic selenide derived from MOF precursor with amazing heterostructure as the advanced anode materials for SIBs.

A magnetically recoverable RuCo bimetallic catalyst was reported for the catalytic hydrogenation of furfural to furfuryl alcohol under ambient H2 pressure. The magnetic catalyst was prepared by H2 treatment of the RuCo composite precursor from a facile one-pot hydrolysis of Co and Ru salts by NaBH4 solution. This catalyst can totally convert furfural to 98-100% furfuryl alcohol at 120 °C under 1 bar H2 in isopropanol or water using only molecular H2 as hydrogen source. Moreover, the catalyst showed excellent stability during recycling test and can be easily and completely recovered by magnet from reaction solution. The influence of Ru/Co ratio and H2-treatment temperature was studied, which were shown to be important for the structural evolution and the metal interaction in RuCo active sites, based on the comprehensive characterizations including XRD, TGA, TEM, XPS, H2-TPR, CO adsorbed DRIFT-IR. It was demonstrated that the cooperative Ru0-Co0 bimetallic active sites in strong interaction can significantly promote activity and selectivity of the catalyst due to an enhanced adsorption and activation of furfural and H2, and simultaneously created a strong magnetism in the RuCo catalyst for simple physical separation.

To improve the Al/Mg bimetallic interface, La was added into the Al/Mg bimetallic interface manufactured by a compound casting process. The effect of La addition on the microstructure, mechanical properties and fracture behavior of the Al/Mg bimetallic interface and the formation mechanism of the interface were studied in detail. Al11La3, Al8Mn4La, Al20Ti2La, and other rare earth precipitates (RE precipitates) preferentially precipitated at the interface with La addition, while the number of the Al11La3 and Al8Mn4La located in eutectic structure area (E area) gradually increased and aggregated in the interface with the increase of the La content. Besides, the matrix structure in different areas of the Al/Mg interface changed in different degrees, and the eutectic structure and primary γ (Mg17Al12) dendrites in the E area were refined, but the intermetallic compounds area (IMC area) had no obvious change. With the addition of the La, the interface was strengthened under the comprehensive effect of refinement strengthening and precipitation strengthening from the E area. When the La content increased to 1.0%, the shear strength of the Al/Mg bimetal reached the maximum of 51.54 MPa, which was 30.95% higher than the group without La addition. However, with the further increase of the La content, the large area aggregation of the Al11La3 and Al8Mn4La occurred in the interface, leading to the separation of the matrix structure of the E area and the decrease of the shear strength of the Al/Mg interface.

The efficacy of treatment with hydrogen and Ag-Cu co-deposition on TiO2 photocatalysts has been investigated computationally and experimentally. The hydrogenated Ag-Cu with co-loaded TiO2 (H:(Ag-Cu/TiO2)) achieved a photoactivity about 110 times that of pristine TiO2, which corresponds to a rate of 1.16 mmol h−1 g−1 for hydrogen generation. Soft X-ray spectra and quantum-chemical calculations indicate that the notable promotion of photoactivity on H:(Ag-Cu/TiO2) is ascribable to the synergy between new electronic states and a lattice distortion. The soft X-ray absorption spectra (XAS) indicated that the TiO6 octahedral symmetry and the Ti 3d- orbital orientation are significantly affected by the Ag-Cu decoration and the hydrogenation treatment. The mechanisms involved in this photocatalysis were studied with soft XAS in situ, which showed that the photoexcited electrons transfer from the bimetallic Ag-Cu to the TiO2 conduction band as the photoresponse of this composite photocatalyst. The strategy of coupling hydrogenation with bimetallic Ag-Cu onto TiO2-based photocatalysis provides a facile and promising solution to other environmental and energy applications.

The water gas shift reaction is of vital significance for the generation and transition of energy due to the application in hydrogen production and industries such as ammonia synthesis and fuel cells. The influence of support doping and bimetallic alloying on the catalytic performance of Pt/CeO2-based nanocatalysts in water gas shift reaction was reported in this work. Various lanthanide ions and 3d transition metals were respectively introduced into the CeO2 support or Pt to form Pt/CeO2:Ln (Ln = La, Nd, Gd, Tb, Yb) and PtM/CeO2 (M = Fe, Co, Ni) nanocatalysts. The sample of Pt/CeO2:Tb showed the highest activity (TOF at 200 °C = 0.051 s-1) among the Pt/CeO2:Ln and the undoped Pt/CeO2 catalysts. Besides, the sample of PtFe/CeO2 exhibited the highest activity (TOF at 200 °C = 0.12 s-1) among PtM/CeO2 catalysts. The results of the multiple characterizations indicated that the catalytic activity of Pt/CeO2:Ln catalysts was closely correlated with the amount of oxygen vacancies in doped ceria support. However, the different activity of PtM/CeO2 bimetallic catalysts was owing to the various Pt oxidation states of the bimetals dispersed on ceria. The study of the reaction pathway indicated that both the samples of Pt/CeO2 and Pt/CeO2:Tb catalyzed the reaction through the formate pathway, and the enhanced activity of the latter derived from the increased concentration of oxygen vacancies along with promoted water dissociation. As for the sample of PtFe/CeO2, its catalytic mechanism was the carboxyl route with a higher reaction rate due to the moderate valence of Pt along with improved CO activation.

Transition metal-based bimetallic oxides can effectively activate peroxymonosulfate (PMS) for the degradation of organic contaminants, which may be attributed to the enhanced electron transfer efficiency between transition metals. Here, we investigated the high-efficiency catalytic activation reaction of PMS on a well-defined bimetallic Fe-Mn nanocomposite (BFMN) catalyst. The surface topography and chemical information of BFMN were simultaneously mapped with nanoscale resolution. Rhodamine B (RhB, as a model pollutant) was used to evaluate the oxidation activity of PMS activation system. The maximum absorption peak of RhB obviously blue shifted from 554 nm to 501 nm, and decreased sharply to disappear completely within 60 min. The removal performance is better than most of the reported single transition metal oxide. X-ray photoelectron spectroscopy (XPS) imaging of the BFMN electronic structure after catalytic activation confirmed that the accelerated internal electron transfer is mainly caused by the synergy effect of Mn and Fe sites at the catalysis boundary. The outstanding ability of BFMN for PMS chemical adsorption and activation may attribute to the enhanced covalency and reactivity of Mn-O. These results of this study can advance understandings on the origins of bimetallic oxides activity for PMS activation and developing the efficient metal oxide catalysts in real practice.

This study demonstrates the direct hydrogenation of polyethylene terephthalate (PET) dissolved in 1,1,1,3,3,3-hexafluro-2-propanol to environmentally friendly polyester polyethylene-1,4-cyclohexanedicarboxylate (PECHD) using a Vulcan XC-72 supported Rh-Pt bimetallic catalyst synthesized via a polyol method. The hydrogenation of PET was promoted by RhOx species present on the catalyst support surface which was generated using the polyol synthesis method. As compared to the monometallic Rh catalyst, the Rh-Pt bimetallic catalyst was found to be superior for hydrogenation of PET. This superiority was attributed to the strong aromatic ring adsorption ability of Rh working in synergy with an increased H2 spillover by Pt. At a H2 pressure of 6.89 MPa and 50 °C for 60 min, complete hydrogenation of PET to PECHD was achieved over the Rh-Pt bimetallic catalyst possessing theoretical Rh and Pt metal loadings of 2.5 wt% each. PECHD was found to be recovered to a very high extent using the compressed CO2 anti-solvent technique after hydrogenation of PET.

16 figures, 10 tables., The deployment of hydrogen as an energy carrier is found to be a vital alternative fuel for the future. It is expected that water electrolysis, powered by renewable energy sources, be able to scale‐up hydrogen production. However, the reaction kinetic of oxygen evolution reaction (OER) is a sluggish process, which predominantly limits the efficiency of water electrolysis. This review recapitulates the recent progress and efforts made in the design and development of two selected earth-abundant bimetallic electrocatalysts (NiCo and CoFe) for alkaline OER. Each bimetal electrocatalyst is thoroughly outlined and discussed in five sub-sections, including bimetal (oxy) hydroxides, Layered double hydroxides (LDHs) structures, oxides, composites, alloy and nanostructured electrocatalysts, and assembled with heteroatoms. Furthermore, a brief introduction to an in situ/operando characterization techniques and advantages for monitoring the structure of the electrocatalysts is provided. Finally, a summary outlining the challenges and conceivable approaches to advance OER performance is highlighted and discussed., Financial support from the European Union’s Horizon 2020 Research and Innovation programme under the Marie Skłodowska-Curie Actions-Innovative Training Networks (MSCA-ITN) Grant Agreement 813748 (Bike project) are gratefully acknowledged. The authors also wish to acknowledge the Ministerio de Ciencia, Innovación y Universidades (MICINN), and FEDER for the received funding in the project of reference ENE2017-83976-C2-1-R.

Electrochemical nitrogen reduction reaction (NRR) has been identified as a prospective alternative for sustainable ammonia production. Developing cost-effective and highly efficient electrocatalysts is critical for NRR under ambient conditions. Herein, the hierarchical cobalt-molybdenum bimetallic sulfide (CoS2/MoS2) flower-like heterostructure assembled from well-aligned nanosheets has been easily fabricated through a one-step strategy. The efficient synergy between different components and the formation of heterostructure in CoS2/MoS2 nanosheets with abundant active sites makes the non-noble metal catalyst CoS2/MoS2 highly effective in NRR, with a high NH3 yield rate (38.61 μg h–1 mgcat.–1), Faradaic efficiency (34.66%), high selectivity (no formation of hydrazine) and excellent long-term stability in 1.0 mol L–1 K2SO4 electrolyte (pH=3.5) at − 0.25 V versus the reversible hydrogen electrode (vs. RHE) under ambient conditions, exceeding much recently reported cobalt- and molybdenum--based materials, even catch up with some noble-metal-based catalyst. Density functional theory (DFT) calculation indicates that the formation of N2H* species on CoS2(200)/MoS2(002) is the rate-determining step via both the alternating and distal pathways with the maximum ΔG values (1.35 eV). These results open up opportunities for the development of efficient non-precious bimetal-based catalysts for NRR.

Hollow nanostructures are extremely attractive in energy storage and show broad application prospects. But the preparation method is accompanied by a complicated process. In this article, the CoZn–based hollow nanoboxes with electrochemical synergy are prepared in a simple way. This structure can effectively shorten the transmission distance of ions and electrons, and alleviate the volume expansion during the cycle. In particular, bimetallic oxides are rich in oxygen vacancies, providing more active sites for electrochemical reactions. In addition, the stepwise oxidation–reduction reaction can also improve the volume change of the electrode material. According to the kinetic analysis and density functional theory (DFT) calculation, it is confirmed that the synergistic effect of the bimetallic oxide can accelerate the reaction kinetics. Based on these characteristics, the electrode exhibits stable cycle performance and long cycle life in alkali metal ion batteries, and can provide reversible capacities of 302.1 (LIBs, 2000 cycles), 172.5 (SIBs, 10000 cycles) and 109.6 (PIBs, 5000 cycles) mA h g–1 at a current density of 1.0 A g–1, respectively. In addition, by assembling (LiCoO2//CoZn–O2) and (Na3V2(PO4)3//CoZn–O2) full–cells, the practical application value is demonstrated. The sharing of this work introduces a simple way to synthesize hollow nanoboxes, and shows excellent electrochemical performance, which can also be expanded in other areas.

Using angle resolved photoemission spectroscopy, the electronic structures of Pt-skin layer of Pt-Co and Pt-Ni alloys are investigated as CO molecules are adsorbed on the surface. Measured Fermi surface maps and band dispersions reflect the signatures of chemical bonding between Pt-skin layer with CO molecules. Furthermore, the degree of chemical bonding strength is estimated from the shift of the participating band structure, exhibiting the reduced chemical bonding strength of CO molecules on both Pt bimetallic alloys. Our results reveal how the surface band structure of Pt bimetallic alloys is modified with molecular orbitals of CO molecules at the surface, revealing the important role of the electronic structure in the determination of chemical properties of bimetallic alloys.

Combining suitable microstructure and dielectric-magnetic synergy effect is conducive to achieve lightweight, broadband, and high-efficiency microwave absorbing materials within low filler loading. Herein, porous carbon polyhedrons coupled with bimetallic CoNi alloys were synthesized by using metal-organic frameworks (MOFs) as a template and subsequent pyrolysis treatment. Electromagnetic analysis indicated that the existence of metal Ni element could influence the wave attenuation capacity effectively, resulting in frequency selective wave absorption performance. Additionally, the pyrolysis temperature was also closely related to wave absorption intensity. The Co2Ni1/C/PVDF composites calcined at 800 °C possessed outstanding wave absorption performance at an ultra-low filler loading of 5 wt%. The minimum reflection loss value achieved -52 dB (10.8 GHz) under the matched thickness of 3 mm. Moreover, the broadest effective absorption bandwidth (RL

Hydrogen energy (H2) has been considered as the most possible consummate candidates for replacing the traditional fossil fuels because of its higher combustion heat value and lower environmental pollution. Photocatalytic hydrogen evolution (PHE) from water splitting based on semiconductors is a promising technology towards converting solar energy into sustainable H2 fuel evolution. Developing high-activity and abundant source semiconductor materials is particularly important to realize highly efficient hydrogen evolution as for photocatalysis technology. However, unmodified pristine photocatalysts are often unable to overcome the weakness of low performance due to their limitations. In recent years, transition metal phosphides (TMPs) were used as valid co-catalysts to replace the classic precious metal materials in the process of photocatalytic reaction owing to their lower cost and higher combustion heat value. What is more, bimetallic phosphides have been also caused widespread concern in H2 evolution reaction owing to its much lower overpotential, more superior conductivity, and weaker charge carriers transfer impedance in comparison to those of single metal phosphides. In this minireview, we concluded the latest developments of bimetallic phosphides for a series of photocatalytic reactions. Firstly, we briefly summarize the present loading methods of bimetallic phosphides (BMPs) anchored on the photocatalyst. After that, the H2 evolution efficiency based on BMPs as cocatalyst is also studied in detail. Besides, the application of BMPs-based host photocatalyst for H2 evolution under dye sensitization effect has also been discussed. At last, the current development prospects and prospective challenges in many ways of BMPs are proposed. We sincerely hope this minireview has certain reference value for great developments of BMPs in the future research.

The elaborative design and construction of first-rank bifunctional oxygen electrocatalysts featuring low price, high activity and strong stability is critical for the large-scale applications of rechargeable Zn-air batteries. Here, a resultful strategy is proposed for fabricating nitrogen-doped 1D beaded-like structure carbon nanofibers uniformly decorated with nitrogen-doped CuCo2O4 nanoparticles (N-CuCo2O4@CNFs) toward boosting oxygen evolution reaction/oxygen reduction reaction (OER/ORR) catalysis. Taking advantage of the synergistic effect between interconnected 1D hierarchical porous carbon nanofiber structure and high catalytic activity of N-doped CuCo2O4 nanoparticles derived from bimetallic MOFs, the N-CuCo2O4@CNFs catalysts possess enhanced reaction kinetics and preferable charge transfer ability. Impressively, the obtained catalysts exhibit prominent electrocatalytic ability and superior stability for OER/ORR, even surpass the commercial RuO2 and Pt/C. More significantly, the Zn-air batteries employing the N-CuCo2O4@CNFs-800 as cathode display a higher power density of 175.6 mW cm−2, a lower charge-discharge voltage gap of 0.82 V at 10 mA cm−2, as well as a better cycling stability with respect to those of Pt/C + RuO2 mixture, demonstrating the great potential of N-CuCo2O4@CNF as a high-efficiency catalyst for clean energy devices.

Bimetallic complexes of hexapyrrole-[Formula: see text],[Formula: see text]-dicarbaldimines consisting of a pair of four-coordinate metal sites adopt a helical closed [Formula: see text]-symmetric form or sigmoidal open forms depending on whether the 2,2[Formula: see text]-bipyrrole subunit at the center of the hexapyrrole chain takes cis- or trans-conformation. X-ray crystallography of a bisNi complex having N-[([Formula: see text]-1-cyclohexylethyl]carbaldimine units at both ends of the hexapyrrole chain revealed a non-symmetric heterohelical open form where the metal coordination sites of opposite helical sense sit on opposite sides of the central 2,2[Formula: see text]-bipyrrole subunit. BisPd complexes preferred a closed [Formula: see text] form and a steric bulk at the 3,3[Formula: see text]-position of the 2,2[Formula: see text]-bipyrrole subunit improved the helical sense bias. A bisPd complex with N-[([Formula: see text]-1-cyclohexylethyl]carbaldimine units adopts a helical closed [Formula: see text] form exclusively with full bias for a [Formula: see text]-helical sense. These bimetallic single stranded helicates were reversibly oxidized to [Formula: see text]-cation radicals at 0.1∼0.3 V vs. a ferrocene/ferrocenium couple and spectroelectrochemistry revealed remarkable absorption and CD spectral changes in the Vis-NIR region.

The collidal bimentalic nanoparticles of ZnO-Ag were prepared by laser ablation technqiue. The sysenthized bimetalic nanoparticles were characterized by UV–Vis spectrophotometry, Scanning Electron Microscopy (SEM), Energy Dispersive X-ray spectrometry (EDX), Raman spectroscopy, X-ray Photoelectron Spectroscopy (XPS), and Photo-Luminescence (PL). These techniques confirmed the formation of the bimetalic nanocompiste and showed that the size distribution of the synthesized bimetallic nanoparticles varied from 30 to 130 nm. The anticancer activity was validated by measuring the cell cytotocicty by MTT (3-(4, 5-Dimethylthiazol-2-yl)-2, 5-Diphenyltetrazolium Bromide) test applying HCT-116 and HELA cancer cell line. The cell lines’ sensitivity was the highest at 10 µg/mL of ZnO-Ag composite. This indicates that the bimetallic composite ZnO-Ag prepared by laser ablation technique is suitable for cancer treatment.

The oxygen evolution reaction (OER) is a crucial process for water splitting. Reducing overpotential is a great challenge because of four electrons transfer and slow kinetics compared to the hydrogen evolution reaction (HER). Highly efficient and stable OER catalyst with low-cost is important for industrial hydrogen production by water splitting. Here we report a simple approach to synthesize free-standing amorphous FexNi77-xNb3P13C7 with the nanoporous structure through electrochemical dealloying. The np-Fe50Ni27Nb3P13C7 exhibits remarkable OER catalytic activity with a low overpotential of 248 mV to achieve the current density of 10 mA cm−2 in 6 M KOH solution. Also, the np-Fe50Ni27Nb3P13C7 exhibits good long-term stability. The improved OER property is due to bimetallic synergy, decreased resistance of charge transfer, nanoporous structure, amorphous nature, and the generation of NiOOH during the OER process. The free-standing amorphous catalysts with nanoporous structure via electrodealloying method provide a promising approach to boost the performance of non-noble metal OER catalysts for the applications.

The present work, in which cellulose isolated from formic acid fractionation (FAC) is decorated with polyetherimide (PEI) to attain highly efficient cellulose-derived PdAgbimetallic catalyst (PdAg-PEI-FAC), has been investigated, and the catalyst properties are characterized by XRD, XPS, BET, ICP-AES and HAADF-STEM. The as-obtained Pd3.75Ag3.75-PEI-FAC exhibits excellent catalytic performance for H2 evolution from a sodium formate-free formic acid (FA) aqueous medium at ambient temperature and the turnover frequency (TOF) reaches a high value of 2875 h-1, which is superior to most of the previously reported Pd-based heterogeneous catalysts supported on a carbon matrix in the literature. The remarkable catalytic activities of PdAg-PEI-FAC result from high dispersion Pd and synergistic effects between the PdAg bimetallic system. Furthermore, the amide (-NH) group in PEI coated on cellulose acting as a proton scavenger efficiently improves the catalytic property of catalyst. In addition, the critical factors affecting H2 release, such as FA concentration, reaction temperature, PdAg compositions and support matrix type, are also evaluated. Based on the experimental results, the probable three-step mechanism of H2 evolution from FA over Pd3.75Ag3.75-PEI-FAC is proposed. In the end, the activation energy (Ea) of Pd3.75Ag3.75-PEI-FAC catalyst is calculated to 53.97 kJ/mol, and this catalyst shows unique robustness and satisfactory re-usability with no loss of catalytic activity after five recycles. The findings in this work provide a novel routine from lignocellulose fractionation towards cellulose-derived catalyst for H2 evolution.

A series of hollow multi-shelled CeO2 (HoMS-CeO2) support materials with tunable shell numbers were fabricated and applied to the catalytic oxidation of toluene. HoMS-CeO2 possess much higher catalytic activity (T90 = 236 ℃) than hollow CeO2 with only a single shell (h-CeO2) (T90 = 275 ℃). The porous multiple-shelled structure has a higher SBET, which strongly promotes gas distribution and provides more active sites. The superiority of this kind of structure was also verified by comparing h-Co3O4 and HoMS-Co3O4. Furthermore, Pt-Co bimetallic nanoparticles were loaded onto HoMS-CeO2. The synergistic effect between Pt and Co was verified by XPS and O2-TPD, which was observed to allow electron transfer between Pt and Co and thus regulate the electronic state of the Pt. Compared with Pt alone, Pt-Co bimetallic nanoparticles could strongly promote the activation of O2 and oxygen mobility, as revealed by a much higher Oads content and a lower oxygen desorption temperature. Of the catalysts prepared in this study, the 1 wt% PtCo3/CeO2 catalyst was found to be the most suitable for toluene oxidation owing to its excellent activity (T90 = 158 ℃), long-term stability, and water resistance. Finally, in situ DRIFTS was employed to investigate mechanism during toluene oxidation and the possible reaction pathway was proposed.