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Rational design of non-precious metal catalysts for efficient oxygen reduction and oxygen evolution reactions (ORR/OER) is important for rechargeable metal-air batteries. Building highly ordered porous structures while maintaining their overall crystalline orderliness is highly desirable, but remains an arduous challenge. Here, we have synthesized bimetallic metal-organic frameworks (MOFs) on highly ordered three-dimensional (3D) polystyrene templates by controlling the nucleation process. The ordered macropores with 190 nm diameters were uniformly distributed on the as-prepared ZnCo zeolitic imidazolate framework (ZnCo-ZIF). Afterwards, 3D ordered micro-meso-macroporous Co-N-doped carbon polyhedrons (3DOM Co-NCPs) was developed by calcination. With the synergy of the highly dispersed Co N C catalytic sites and the distinct porous structure, the synthesized 3DOM Co-NCPs exhibit impressive bifunctional activity. Additionally, the 3DOM Co-NCPs-900 for Zn-air battery exhibits extraordinary power density, high energy density, and acceptable stability. This approach offers a useful strategy for the fabrication of highly efficient electrocatalysts with 3D ordered porous.

A novel photoactive porous material of GR/FeMIL-101 based on FeMIL-101 metal organic frameworks (MOFs) was successfully synthesized via a simple hydrothermal method. The structural and photoelectric properties of the GR/FeMIL-101 was analyzed by XRD, SEM, TEM, TGA, XPS, UV–vis DRS, FT-IR, PL and EIS methods. The photocatalytic performance for the selective oxidation of benzyl alcohol with GR/FeMIL-101 as catalysts was evaluated under visible light irradiation. The results showed that the GR/FeMIL-101 nanohybrid had better photocatalytic performance than both of FeMIL-101 and the pristine MIL-101. It was further found that the incorporation of Fe and MIL-101 caused valence fluctuations of Fe3+/Fe2+ which improved the absorption of visible-light and increased the separation efficiency of photogenerated charges. In addition, the combination of FeMIL-101 and GR could further promote the transfer rate of the photoelectrons. The mechanism of the reaction revealed that ·O2− was the dominating active specie in this reaction through active species trapping experiments. Fe doped MIL-101/GR nanohybrid was successfully synthesized as an efficient photocatalyst for selective oxidation of alcohols under visible-light and shown a best conversion of 50%. Analyses revealed that Fe was successfully doped into the MIL-101, valence fluctuation of Fe2+/Fe3+ not only improved the visible-light absorption but also increased the separation rate of photoexcited carriers. Graphene further improved the transportation rate of electron (e-). Subsequently, the possible photocatalytic mechanism for the selective oxidation of alcohols was proposed. It was proved that superoxide radicals (·O2-) was the main active species when the reaction was performed under Oxygen atmosphere.

The construction of excellently performing electrocatalysts for hydrogen evolution reaction (HER) with a low-cost and economical strategy is still struggling with an enormous challenge in electrochemical water splitting. In this work, a novel N-doped porous carbon substrate constructed heterojunction electrocatalyst (MoS2-MoP/NC) was fabricated by a simple and facile method. Based on the electronic interaction and synergistic effect between MoS2 and MoP phases, the fabricated MoS2-MoP/NC heterojunction catalyst exhibited excellent electrocatalytic ability. In addition, the N-doped porous carbon substrate had a good charge/mass-transfer ability, which could effectively facilitate electronic transmission or prevent the aggregation of MoS2-MoP nanosheets and improve the catalytic activity. The heterojunction catalyst significantly improved HER activity with a low overpotential of 83 and 103 mV at 10 mA cm−2 in a 1.0 M KOH and 0.5 M H2SO4 and Tafel slope of 59.38 and 59.20 mV dec−1 for HER, respectively. This work provides a simple, less expensive and efficient approach for constructing high-performance heterojunction catalysts for HER.

Reasonable design and synthesis of high-efficiency rare earth oxides-based materials as alternatives to noble-metal catalysts are of great significance for oxygen electrocatalysis. Herein, we report three-dimension (3D) Rosa centifolia-like CeO2 encapsulated with N-doped carbon (NC) composites (CeO2@NC) for enhancing oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) activities. This synthetic method allows CeO2 to tune the oxygen vacancy concentration and electronic structure of a series of CeO2@NC catalysts due to its large oxygen-storage-capacity (OSC) property. Moreover, benefiting from the exposed active sites in NC as well as the synergy between CeO2 and NC, among as-prepared samples, the resultant CeO2@NC-900 delivers a half-wave potential (E1/2) of 0.854 V, which is more positive compared with counterpart of NC-900 (0.806 V) and even comparable to that of commercial Pt/C catalyst (0.855 V). This indicates that the ORR electrocatalytic activity of CeO2@NC-900 is significantly improved. Meanwhile, CeO2@NC-900 exhibits satisfactory performance toward OER. For practical application, the CeO2@NC-900 involved rechargeable Zn-air battery possesses excellent energy efficiency, superior stability, and large energy density (666.1 Wh kgZn−1 at 5 mA cm−2). This approach provides a valid way to develop advanced rare earth oxides-based materials for energy applications.

Novel Fe3C nanoparticles that decorate three-dimensional N-rich porous carbon (Fe3C@3DNC) catalysts were designed and synthesized by double templates assisted high-energy ball milling and subsequent high-temperature pyrolysis for the oxygen reduction reaction (ORR). NaCl and Na2SiO3 are used as the mixed template while Fe(NO3)3·9H2O and 2-Methylimidazole were used as the iron, nitrogen and carbon sources. The optimized Fe3C@3DNC catalyst (Fe3C@3DNC-1-900) had good ORR performance in alkaline medium, with an Eonest value of 0.968 V and E1/2 value of 0.861. In addition, the catalytic process exhibited selectivity–nearly four-electron transfer kinetics and possesses a lower Tafel slope compared to commercial Pt/C catalyst as well as good methanol tolerance. In addition, the Fe3C@3DNC-1-900 catalyst also had excellent ORR activity (E1/2 = 0.72 V) and long-term stability (the half-wave potential only occurs at 10 mV after 5000 cycles) in acidic media. The good catalytic performance of the Fe3C@3DNC-1-900 catalyst can be attributed to the 3D hierarchically porous structure and extremely high number of active sites around the porous carbon. The double template assisted high-energy ball milling strategy can be a promising and scalable method to prepare three-dimensional porous carbon-based composite materials for energy conversion and storage applications.

The introduction of defects can enhance the active sites on transition metal dichalcogenides, which can cause changes in crystal structures, and then lead to a change in the original catalytic performance. Herein, an efficient method of introducing defects was reported. In this method, high-energy iron ions were irradiated on the surface of Bi2Te3 nanosheets by ion irradiation technology, which resulted in the generation of a variety of defects. Compared to the original Bi2Te3 nanosheets, the Bi2Te3 nanosheets irradiated by iron ions showed significant improvement in the hydrogen evolution reaction performance in acidic solution. After the iron ion irradiation, the electric double layer capacitance of the Bi2Te3 nanosheets increased significantly, which indicated an increase in the number of active sites on the surface of Bi2Te3. Analysis of high-resolution transmission electron microscopy images reveals the occurrence of various defects on the surface of Bi2Te3 after the iron ion irradiation, which increased the active sites. Moreover, the conductivity of the iron ion-irradiated Bi2Te3 nanosheets was also significantly improved. It is noteworthy that iron ion irradiation changed the characteristic of the Bi2Te3 surface from hydrophobic to hydrophilic, which facilitated the release of hydrogen bubbles from the catalyst surface and exposed the active sites in time. At the same time, the damage caused by the large bubbles to the electrode material could be avoided, and the stability of the material was improved. This efficient iron ion irradiation method provides an innovative idea for the design of other high-efficient catalysts.

Doping has been widely recognized as an effective method for adjusting the performance of electrocatalysts. It can cause changes in the electronic structure of substances. Thereby, it can affect the intrinsic catalytic performance. Herein, we report a facile doping method in which phosphorus can be simultaneously doped into both CoTe2 and C. In the acidic solution, the hydrogen evolution reaction (HER) performance of the obtained P-CoTe2/C nanoparticles was significantly improved compared with that of undoped nanoparticles. At a current density of 10 mA cm-2, the overpotential decreased from 430 mV to 159 mV. Density functional theory (DFT) calculations show that phosphorus doping can produce new high activity Co-P catalytic sites. In addition, phosphorus can be doped into the carbon in the composite at the same time, which enhances the electrical conductivity of the composite. Moreover, in the process of calcination and doping, the electric double layer capacitance (Cdl) of the composite is significantly increased, which helps in exposing more active sites. This work has developed a multi-effect doping method that simultaneously increases the intrinsic activity, conductivity and active sites of the material. This method provides a new strategy for the performance regulation of other electrocatalysts.

Transition metals and heteroatom doped porous carbon materials have become sone of the most promising catalyst candidates to replace noble metal catalysts for high efficiency oxygen reduction reactions (ORR). Currently, however, the widely used hard templating method for preparing such materials is often complicated and expensive. Here, we develop a rapid gas foaming process to prepare a novel Fe nanoparticle modified N-doped three-dimensional porous carbon framework (Fe/3DNC) catalyst with a controllable microscopic morphology and catalytic efficiency by regulating the amount of urea. It is found that the optimized Fe/3DNC-2 catalyst has a high specific surface area (438 m2 g−1), hierarchically porous structure and homogeneous distribution of active sites (pyridinic N, graphitic N and FeNX). Thanks to the unique 3D framework architecture, the Fe/3DNC-2 catalyst exhibits a remarkable activity and long-term durability towards the ORR, such as a half-wave potential (E1/2 = 0.874 V vs. RHE) and onset potential (EOnset = 0.995 V vs. RHE) which is more positive than that of a commercial noble metal catalyst (20% Pt/C, E1/2 = 0.848 V, EOnset = 0.973 V) in an alkaline medium, and a half-wave potential with only a slight negative shift of approximately 7 mV after 5000 cycles.

Currently, designing and preparing low-cost and high-efficiency electrocatalysts still remains of huge impediment for direct ethanol fuel cells (DEFCs). In this work, by leveraging the unique superiority of Co3[Co(CN)6]2 (Prussian blue analogues, PBA) precursor, we used Pt4+ to replace partial dispersed Co2+ in Co3[Co(CN)6]2 and a metal–organic framework (MOF) derived PtCo electrocatalyst (MD-PtCo/C) was successfully fabricated. Notably, as-obtained MD-PtCo/C (Pt, 0.9532 wt.%) electrocatalyst achieves high utilization rate of ultra-low Pt load and exhibits favorable electrocatalytic performance with lower onset potential, higher EOR activity, less activation energy (Ea) value and better stability compared to commercial Pt/C for ethanol oxidation reaction (EOR). Moreover, the consequence of concentrations (KOH, C2H5OH) and temperatures on electrocatalytic activity of EOR have also been studied. This study would be supportive of developing highly active and low-cost electrocatalysts for other catalytic applications.

To assess the mechanism and milder conditions for amines to imines, UiO-66-NH2 was chosen as an efficient photocatalyst for the transformation under light irradiation. A series of experiments for the catching of the active species were performed, and it was proved that holes (h+) and superoxide radicals ( O2−) were involved when the reaction was performed under air. The reaction also occurred because of the presence of nitrogen-centered radical cations and carbon-centered radicals, which were induced by photogenerated hole (h+) with considerable conversion and selectivity under anaerobic conditions. Our experiments revealed that the catalyst can be recycled for four times.

Developing non-noble metal catalysts with high performance to reduce the cost of hydrazine fuel cells is urgent. Herein, in this study, a series of carbon-supported phosphatized CuNi catalysts (P- CuxNiy/C) are designed for hydrazine oxidation reaction (HzOR) via high temperature phosphating process. Among them, the P Cu2Ni/C is found to be a promising candidate for hydrazine electrooxidation. Electrochemical measurement results indicate that the P Cu2Ni/C catalyst exhibits higher catalytic activity and stability for HzOR in comparison with P CuNi/C, P CuNi2/C, Cu2Ni/C, Cu/C and Ni/C catalysts. Additionally, HzOR kinetics are also investigated, and it proves that hydrazine electrooxidation on P Cu2Ni/C is a diffusion controlled irreversible process. Meanwhile, physical characterization reveals that the catalysts have doped phosphorus successfully. All results demonstrate that as-prepared P Cu2Ni/C catalyst is a promising electrocatalyst for direct hydrazine fuel cells.

The flame synthesis provides a simple low-cost method to produce novel carbon materials. In this study, N, B co-doped carbon (N B C) materials have been prepared by flame synthesis. Among many as-prepared samples, the N B C catalyst which prepared under carbonization temperature of 1000 °C for 3 h with acetonitrile/acetone precursor of 1:1 exhibits the best catalytic activity and stability, as well as good resistance to methanol interference for oxygen reduction reaction (ORR), with half-wave potential being almost nearly to Pt/C, and a quasi-four-electron transfer process. This study would provide an economic, environmental feasible and scalable approach for fabricating novel heteroatom co-doped carbon materials for ORR applications.

To achieve high-energy density of supercapacitors and maintain their intrinsic high power density, the operating voltage should be extended by assembling high specific capacitance electrode materials into an asymmetric supercapacitor (ASC) device. Herein, an ASC was assembled based on a three-dimensional (3D) interconnected porous carbon framework (PRPC-1K) as a negative electrode and 3D sphere-like nickel nitride (Ni3N) nanosheets as a positive electrode in an aqueous KOH electrolyte. The PRPC-1K was prepared by a simple activation process with biomass poplar root as the carbon precursor, and the Ni3N nanosheets were successfully synthesized via a simple low-temperature hydrothermal and further urea-assisted nitridation process. Due to the unique structures and high capacitive performances of these materials, the Ni3N//PRPC-1K ASC assembled based on these two materials achieved the high energy density of 30.9 W h kg−1 at the high power density of 412 W kg−1 and acceptable electrochemical cycling stability with an 81% retention after 5000 cycles.

The search for non-precious-metal catalysts with low cost, high activity and stability to substitute Pt in oxygen reduction reaction (ORR) attracts tremendous attention. Herein, novel ORR electrocatalysts of cerium species embedded N-doped carbon (CENC) materials are prepared by the chemical oxidative polymerization and pyrolysis methods, using polyaniline-coated cerium organic complex (Ce(TTA)3Phen) as the precursor. The experimental results have revealed that the electrocatalytic activity of the obtained electrocatalysts for ORR is affected by the pyrolysis temperature. Remarkably, the as-prepared CENC-1000 exhibits a good catalytic activity in terms of limiting current density, onset potential and half wave potential, as well as superior tolerance to methanol crossover for ORR as comparable to commercial Pt/C in alkaline media. The high performance is attributed to the introduction of nitrogen active sites and Ce active species (generated from the pyrolysis of CENC precursor), which endow CENC-1000 with enhanced electrocatalytic activity. This approach makes CENC-1000 a promising candidate as cathode catalyst in renewable energy conversion devices.

The exploration of photocatalysts used in converting CO2 into applicable organic products is of significant importance for addressing the universal problems of both global warming and energy shortage. In this work, the sensitizer Cu(II) tetra(4-carboxylphenyl)porphyrin (CuTCPP) was successfully combined with hydroxylated commercial P25 (TiO2) by hydrothermal treatment (denoted as P25m). The as-prepared composite CuTCPP/P25m shows photocatalytic activity for CO2 reduction to give methane under UV-vis irradiation. The characterizations entailed in our work not only confirm the effective combination of the composite, but exhibit a stronger light absorption capability than P25m. During the photocatalytic evaluation, the photocatalytic system employing 0.5% CuTCPP/P25m (CuTCPP account for 0.5% in the total amount) engendered approximately 46 times higher methane than generated by P25m alone. This impressive amelioration can be attributed to a strengthened capability of CuTCPP/P25m in light absorption and enhanced separation efficiency of photo-induce electrons and holes.

It is highly desirable but challenging to develop and construct a high activity, good stability and cost-effective catalyst system applied for oxygen reduction reaction (ORR). In this study, a series of CeNiOx@CN-n catalysts (carbonized polypyrrole coated CeNiOx) is prepared by an in-situ polymerization method. The effects of bimetal component and nitrogen-doped carbon layer thickness in a “nitrogen-doped carbon layer-oxide composite” system are explored for ORR. It shows that the atomic ratio of Ce: Ni = 1:1 is the optimal ratio, and the ratio of polypyrrole: oxide = 1: 1 is the optimal layer thickness. As the best-performing electrocatalyst, CeNiOx@CN-4 follows a 4e− pathway for ORR. Moreover, it exhibits good electrocatalytic activity and stability. Especially, its ability of anti-methanol poisoning is stronger than that of Pt/C catalyst. Predictably, this “nitrogen-doped carbon layer-oxide composite” system would open up a potential way to design more efficient electrocatalysts.

In this study, rare-earth bimetallic carbide CeLa2Cx-NC has been prepared by a facile pyrolysis of o-phthalic anhydride, melamine and rare-earth elements (Ce and La). The as-prepared CeLa2Cx-NC electrocatalyst shows satisfactory electrocatalytic activity towards oxygen reduction reaction (ORR) in alkaline electrolyte, as well as good suffering from methanol and CO poisoning, and superior stability than commercial Pt/C. It demonstrates that this rare-earth bimetallic carbide would provide a neoteric avenue for the development of ORR catalyst.

The development of biomass-derived nitrogen-doped porous carbons (NPCs) for the oxygen reduction reaction (ORR) is important for sustainable energy systems. Herein, NPCs derived from Astragali Radix (AR) via a cost-effective strategy are reported for the first time. The as-prepared AR-950-5 catalyst shows a stacked layer-like structure and porosity. Notably, the optimized AR-950-5 delivers catalytic activity comparable to that of commercial Pt/C (C-Pt/C), with high onset potential, positive half-wave potential and large limiting current density. It also displays superior long-term stability and methanol tolerance for ORR. This work will pave the way for a new approach in the development of highly active and low-cost NPCs for fuel cells.

A set of multiple cation-doped linear polymers (abbreviated as OPY-1,2-BE, OPY-1,4-BB, OPY-1,8-BO, OPY-1,4-OBB) synthesized from a dipyridine derivative (OPY) and dibrominated compounds were employed as fluorescent probes for adenosine triphosphate (ATP) sensing. Among them, OPY-1,8-BO is particularly able to recognize ATP over its related compounds adenosine diphosphate (ADP), adenosine monophosphate (AMP), and other phosphate anions, with very desirable switch off–on performances. The interesting phenomenon of aggregate-induced emission (AIE) is proposed as the main reason for the ATP sensing, which is due to the ATP being more negative than the polymers and therefore there is more opportunity for connections with the multiple cation doped polymers through electrostatic attractions. Cell imaging measurements were carried out and demonstrated that even though these probes bear the same OPY core and only slightly different linkers, they are able to image different cell environments. The controlled cell imaging verified that the OPY-1,8-BO probe has ATP-specific recognition in living cells.

Herein, uniform cobalt manganese hydroxide (CMOH) nanoneedle arrays were firstly prepared via a low-temperature hydrothermal process using nickel (Ni) foam as a nanoneedle growth support framework. Subsequently, stable and integrated heterostructures of cobalt–manganese sulfides (CMS) with porous structures can be simultaneously formed and grown through the reaction of CMOH with Na2S during the hydrothermal anion-exchange reaction process while retaining their intrinsic nanoneedle array structure. The as-prepared CMS nanoneedle arrays as binder-free electrodes for supercapacitors exhibit a high area capacity of 0.53 mA h cm−2 at 2 mA cm−2 and good rate performance, as well as outstanding cycle life (only 6.3% capacity loss after 1500 cycles). Based on the unique architecture and excellent electrochemical performance of CMS nanoneedle arrays, a novel CMS-8//AC asymmetric supercapacitor with a high operating voltage of 1.7 V was fabricated using CMS nanoneedle arrays as the positive electrode and activated carbon (AC) as the negative electrode, respectively, and provided a maximum specific energy of 48.5 W h kg−1 at a specific power of 524.5 W kg−1. Such excellent electrochemical behaviors suggest that the CMS nanoneedle arrays are promising electrode materials for high performance supercapacitors. Moreover, the present synthesis strategy can be extended to prepare other porous, integrated and heterostructured metal compounds.

Designing and preparing highly efficient non-precious metal catalysts for oxygen reduction reaction (ORR) in alkaline medium still remains a big challenge. In this study, we successfully prepared a series of NdCuOx@CN catalysts via encapsulating bimetallic NdCuOx nanoparticles into nitrogen doped carbon (CN), which combines the advantages of rare-earth-transition bimetallic oxides and CN. And we obtained an optimal ORR catalyst (NdCuOx@CN-1000) by exploring the ratio of NdCuOx to aniline in the precursors and carbonization temperature. The optimal NdCuOx@CN-1000 catalyst yields comparable ORR activity to commercial Pt/C catalyst and exhibits excellent stability as well as tolerance to methanol crossover. This excellent performance is attributable to the formation of encapsulated structure and CN composite. Simultaneously, synergistic effect between different components in the catalyst also boosts the ORR performance.

Nitrogen-containing carbon materials from sustainable chemicals are of great interest for energy conversion technology. As a natural, nontoxic, biological and economical compound, riboflavin is promising for designing and producing nitrogen-containing carbon support materials for fuel cells. Herein, a novel carbon material is obtained by H2SO4 pre-carbonized and heat treatment steps from riboflavin (riboflavin-derived carbon, named as R-C), which is used as support to immobilize Pd nanoparticles (Pd/R-C). The results show that, compared with conventional Pd/C prepared from XC-72R support, the Pd/R-C catalyst exhibits larger electrochemically active surface area (EASA) and higher electrocatalytic activity and stability towards ethylene glycol oxidation (EGOR). The effects of temperature scan rates, ethylene glycol, and KOH concentrations on EGOR are also investigated, respectively.

A ternary Ni 5 Sm-P/C electrocatalyst is successfully prepared for urea electrooxidation. Physical characterization reveals that the addition of samarium (Sm) and phosphorus (P) to nickel (Ni) can change the electronic configurations of the Ni 5 Sm-P/C catalyst, leading to more active form of NiOOH. Electrochemical measurements show that the Ni 5 Sm-P/C catalyst exhibits exceptionally high activity and good stability for the electrooxidation of urea. Notably, the anodic peak current of Ni 5 Sm-P/C catalyst is over 1.5 times, 21 times and 29 times higher than that of Ni-P/C, Ni 5 Sm/C and Ni/C, respectively. The high activity on Ni 5 Sm-P/C owes to the synergistic contribution among Ni, Sm and P. All results demonstrate that adding metal and non-metallic components into Ni/C catalyst will provide a valuable resource of research and practical application for improving the performance of direct urea fuel cells.

Heteroatom-doped porous carbon materials have been widely investigated as cost-effective oxygen reduction reaction (ORR) catalysts. In this study, a series of nitrogen, phosphorus co-doped porous carbon (NP-PC) catalysts are prepared and characterized. Optimized precursors’ mass ratio, suitable pyrolysis temperature and appropriate heating rate are intensively studied. Notably, among as-prepared catalysts, NP-PC-950-10 executes an approximate 4e− oxygen reduction pathway and delivers a nearly equal ORR performance to that of commercial 20 wt.% Pt/C (C-Pt/C) catalyst. The stability and methanol crossover resistance of NP-PC-950-10 are also superior to C-Pt/C. These superior electrocatalytic performance may be ascribed to its well-developed porous structure, large Brunauer–Emmett–Teller (BET) surface area (1050.45 m2 g−1), and good synergistic effect between nitrogen and phosphorus. This study will provide a new insight for exploring cost-efficient non-precious metal electrocatalyst of clean energy conversion systems.

The leaf-like structure BiVO4 electrode and MFe2O4/BiVO4 (M = Ni, Co) composite photoelectrodes were prepared by electrochemical deposition, ensuing heating treatment and electrophoretic deposition technology. The characterizations of SEM, XRD and DRS indicated that the BiVO4 derivatives mainly existed in small nanoparticles with monoclinic phase and exhibited stronger light absorption capability than that of pure BiVO4. Hereon, the respective photoelectrochemical (PEC) activities of BiVO4 and its derived composites were systematically studied. The results suggested that the NiFe2O4/BiVO4 and CoFe2O4/BiVO4 not only showed higher photocurrent response values at 1.23 V vs. NHE than pure BiVO4 electrode under visible light illumination, but also played a superior PEC hydrogen evolution performance, which was considered owing to their strong absorption to light, reduction combination of carriers and effective separation of electrons and holes.

Developing non-precious catalysts with high activity and superior durability is eager demand for the wide spread fuel cells. In this study, a novel kind of nitrogen-doping carbon based material (PR-C) has been fabricated with phenolic resin and chitosan, in which the low-cost and renewable biomass material chitosan is used as the nitrogen source. Notably, compared with Pt/C, among the resultant catalysts, the PR-C (1:3.5) catalyst has long-term stability, superior tolerance to methanol poisoning, and favorable electrocatalytic activity for oxygen reduction reaction (ORR). Consequently, as-prepared catalyst (PR-C) utilized phenolic resin/chitosan is promising as a low-cost and renewable catalyst for ORR.

Herein, a series of non-precious metal catalysts, nitrogen, phosphorus co-doped porous carbon (NP-PC) materials are successfully fabricated via a facile pyrolysis and activation strategy employing low-cost precursors. Among all prepared catalysts, the optimized NP-PC-0.5 (with 0.5 wt% FeCl3) possesses comparable catalytic activity to that of state-of-the-art commercial Pt/C (C-Pt/C) catalyst. Noticeably, it exhibits significantly superior methanol crossover resistance and better stability than C-Pt/C. The synergetic effect between nitrogen and phosphorus, together with nanoporous structure endow NP-PC-0.5 with practical significance of applicability, rendering it as a promising candidate of Pt-based electrocatalysts in fuel cells. This preparation approach is facile and scalable for fabricating non-precious metal electrocatalysts.

Composite of FeCo alloy embedded in nitrogen self-doped biocarbon was faciely prepared by pyrolysis of precursor of eggshell membrane mixed with nitrates. Three samples were prepared at different pyrolysis temperatures and well characterized by transmission electron microscopy (TEM), Raman spectrometry, X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and N2 adsorption-desorption analysis. The as-prepared samples exhibit high electrocatalytic activities toward oxygen reduction reaction under alkaline conditions. Especially, the sample pyrolyzed at 800 °C exhibits superior electrocatalytic activity, stability and resistence for methanol corrosion compared with commercial Pt/C (20%) and exhibit a four-electron ORR pathway in alkaline condition. The catalyst also exhibits brilliant capacity of supercapacitor.

To combine with the advantages of selenium functionalized carbon and bimetallic-alloy nanoparticles (NPs), a novel Se-C supported Pd3Sn (Pd3Sn/Se-C) electrocatalyst was successfully prepared and estimated towords glucose oxidation reaction (GOR) in alkaline medium. The results demonstrate that Pd3Sn/Se-C electrocatalyst possesses superior catalytic performance towards GOR. Specifically, it presents larger electrochemically active surface area, higher electrocatalytic activity and better cycling stability compared to those of Pd3Sn/C, Pd/Se-C and Pd/C. This satisfactory result mainly owes to the special properties of Se-functionalized carbon material, as well as the synergetic effect between Pd3Sn NPs alloy and Se-C support. Additionally, the effects of the concentration of electrolyte and glucose as well as the temperature on the activity for GOR have been investigated. This work will shed new light on the investigation of excellent Se-functionalized-support based electrocatalysts in the future.

Exploring non Pt-based catalysts with high ORR performance still remains a great challenge in the development of energy conversion and storage devices. The aim of this study is preparing a novel ORR catalyst (Sm2O3 embedded in nitrogen doped carbon by calcination processes, named as Sm2O3-CN-1100) to substitute Pt catalysts. And the results of this study show that Sm2O3-CN-1100 displays good electrocatalytic activity towards ORR, with high stability, strong tolerance to methanol crossover, and a quasi 4-electron transfer process, making it a promising Pt alternative ORR catalyst. The satisfactory ORR performance would result from the mosaic structure of Sm2O3 embedded in nitrogen doped carbon layer and the strong coupling effect between Sm2O3 and nitrogen doped carbon.

Metal-organic frameworks (MOFs), a new class of porous crystalline materials, have attracted great interest as fascinating applications for eco-friendly photocatalysts. In this study, new hybrid MOFs, iron doped zirconium based metal-organic frameworks, FeUiO-66, were successfully synthesized by hydrothermal method firstly. Then the PANI/FeUiO-66 nanohybrids were fabricated through annealing process. The photocatalytic performances of the obtained PANI/FeUiO-66 nanohybrids were evaluated by selectively oxidation of various alcohol substrates using molecular oxygen as a benign oxidant. Boosting by synergistically multi-doped effect, the catalytic activity of the novel PANI/FeUiO-66 is remarkably higher than that of bare UiO-66 under visible light irradiation at ambient temperature. Further analyses revealed that the enhancement of photocatalytic activity originated from the two aspects. On one hand, when the Fe doped into the framework, valence fluctuation of Fe 2+ /Fe 3+ could reduce the recombination rate of photoexcited carriers. On the other hand, based on energy band matching between FeUiO-66 and PANI, the easily formed heterostructures from PANI and FeUiO-66 can efficiently enhance the separation of photogenerated carriers. Furthermore, by virtue of unique advantage of the position of the CB and VB of FeUiO-66, alcohols could be selectively oxidized by the O 2 − and h + . Remarkably, it is expected that the MOF-conductive conjugated polymers nanohybrids could be used as efficient visible light driven photocatalysts for organic transformation with high selectivity under eco-friendly conditions.

In this study, cerium carbide embedded in nitrogen-doped carbon (CeC x -NC) has been prepared by a facile pyrolysis of melamine formaldehyde resin containing rare-earth element. The as-prepared CeC x -NC catalyst shows high electrocatalytic activity towards oxygen reduction reaction (ORR) in alkaline electrolyte, with the half wave potential being almost equal to commercial Pt/C, nearly four electron transfer number, good toxicity tolerance durability and cycle stability. This rare-earth metal carbide opens a novel avenue for advanced electrocatalyst.

Pt-rare-earth alloys are rarely studied as electrocatalysts for direct ammonia fuel cells. Thus, their electrocatalytic performance of ammonia electro-oxidation is worth studying, especially for Pt x Eu alloys. Herein, a series of Pt x Eu/C (x = 1, 3 and 5) electrocatalysts has been prepared using polyol reduction method. Among them, PtEu/C is found to be a promising candidate for ammonia electro-oxidation. Physical characterizations show that PtEu/C has a small lattice parameter and narrow size distribution. X-ray photoelectron spectroscopy peak shifts of PtEu/C indicate the electron transfer from Eu to Pt. Electrochemical measurement results indicate that PtEu/C is highly active. Particularly, it has a higher current density, lower activity loss and apparent activation energy toward ammonia electro-oxidation compared to Pt/C catalyst.

An electrocatalyst made by Pd 3 Cu alloy nanoparticles (NPs) supporting on nitrogen-doped mesoporous carbon (NMC), Pd 3 Cu/NMC, is applied to glycerol oxidation reaction (GOR). In this study, the nano-Al 2 O 3 as a hard template, phenolic resin and melamine as nitrogen-containing carbon precursor afford a nitrogen-doped mesoporous carbon support that shows satisfactory effect in stabilizing Pd 3 Cu alloy NPs. Owing to the strong superimposed effect among nitrogen-doping, mesoporous structure and alloying action, the as-prepared Pd 3 Cu/NMC catalyst has high catalytic performance for GOR in alkaline medium. Notably, compared with Pd/C, the Pd 3 Cu/NMC exhibits higher oxidation peak current, better stability and lower activation energy. It is also found that glycerol electrooxidation on Pd 3 Cu/NMC catalyst is a diffusion controlled irreversible process. All results demonstrate Pd 3 Cu/NMC is an excellent electrocatalyst in GOR.

Photocatalytic synthesis using visible light is a desirable chemical process because of its potential to utilize sunlight. A heterostructured MIL-125/Ag/g-C3N4 nanocomposite was implemented as an efficient bifunctional visible-light response catalyst for the photoreduction of nitrocompounds and the oxidation of alcohols. The photocatalyst was prepared via an accessible method and characterized by XRD, SEM, TEM, XPS, FT-IR, N2 adsorption–desorption isotherm, UV–vis DRS, PL and EIS. The reactive efficiency of the photocatalyst depends on two primary factors, one is the light adsorption of catalysts, Ag nanoparticles (NPs) were photodeposited on the surface of g-C3N4 and MIL-125 to increase visible-light absorption via the surface plasmon resonance. And the other is the separation efficiency of the photogenerated charge carrier. As an electron-conduction bridge in the interface between MIL-125 and g-C3N4, Ag NPs could facilitate the direct migration of photoinduced electrons from g-C3N4 to MIL-125 and retard the recombination of electron-holes. Therefore, the MIL-125/Ag/g-C3N4 sample shows highest photocatalytic activity compared with MIL-125, g-C3N4, MIL-125/Ag and MIL-125/g-C3N4. A corresponding photocatalytic mechanism of these reactions was discussed in detail. Moreover, the photoreduction of nitrocompounds and oxidation of the alcohols with superior conversions and selectivities were obtained, and the catalyst can be recycled four times. It is concluded that MIL-125/Ag/g-C3N4 would be a promising visible light photocatalyst in the field of selective organic transformations.

Compressible supercapacitors are novel energy-storage devices that can be used in elastic electronics; however, the performance of the supercapacitor depends mainly on its electrode materials and configuration. Herein, free-standing three-dimensional hierarchical porous polypyrrole (PPy) wrapped nitrogen-containing polyaniline based carbon nanospheres (NPACNS) are prepared and coated on the skeleton of sponge composite electrodes (PPy/NPACNS/sponge) via dipping and drying and chemical oxidation polymerization methods. Furthermore, an integrated highly compressible all-solid-state supercapacitor is fabricated using PPy/NPACNS/sponge as the electrode and polyvinyl alcohol (PVA)/LiClO4 gel as the electrolyte, which demonstrates an outstanding electrochemical performance of 95 F g−1 (2.8 F cm−3) specific capacitance, 3.3 W h kg−1 (0.1 mW h cm−3) energy density and 93% capacitance retention after 1000 cycles. Surprisingly, the electrochemical performance of the as-fabricated device remains nearly unchanged when it is compressed under 50% strain, and its specific capacitance and compressibility are well maintained after 400 repeated compressing-releasing cycles. More importantly, due to its solid-state and integrated configuration, several compressible supercapacitors can be conveniently interconnected together in series on one chip to power electronics. This device will pave the way for advanced supercapacitor applications in compressible energy storage devices that are compatible with compression-tolerant electronics.

In this work, we fabricated a novel triphenylamine-derivative (DNDT)-modified nanographene oxide by following a simple gram-scale method. The product showed interesting optical properties and good potential for use in bioimaging applications. This fluorescent carbon material could be readily internalized by HepG2 cells and was clearly visualized to accumulate mainly in the nucleus.

It is desirable to engineer bio-compatible construction materials and cargo release vehicles with efficient cargo loading capability and controlled drug delivery ability. Herein, an inorganic–organic hybrid composite DNDT&SiO2–NH2@BSA was established using two steps. Technologically, the fluorescent DNDT was grafted on the particles surface via solid phase synthesis, which was able to report the occurrence of interactions between the silica cores and proteins of bovine serum albumin (BSA) by real-time optical change analysis. It should be noted that the construction method derived from this study can be transposed easily to other surface modification procedures. Interestingly, DNDT&SiO2–NH2@BSA could be dispersed into an aqueous phase very well, leading to a homogeneous distribution of the drug over the matrix with a more efficient manner. Furthermore, due to the temperature-dependent α-helix content changes, the encapsulators of BSA can capture the drugs at low temperature and release them with elevating temperature. In particular, a desirable controlled release is realized at 37 °C.

A primary challenge of gel electrolytes in the development of flexible and wearable devices is their weak mechanical strength and poor electrochemical performances. Here, we prepare a novel PVA (polyvinyl alcohol)–H2SO4–BAAS (bromamine acid sodium) gel polymer with a porous network structure as both electrolyte and separator, which achieves excellent mechanical strength, maintains a high ionic conductivity of 21.4 mS cm−1 and provides a reversible redox reaction for enhanced supercapacitor performance. Surprisingly, the operating voltage of the present active electrolyte enhanced supercapacitor (AEESC) is up to 1.5 V, which is much larger than that of the previously reported active electrolyte based supercapacitors (about 1.0 V). Furthermore, the AEESC exhibits a maximum specific capacitance of 390 F g−1 at a current density of 0.8 A g−1, a remarkably high energy density of 30.5 W h kg−1 at a power density of 600 W kg−1 and good cycling stability. Additionally, such a device displays only a small capacitance loss when the gel polymer is under a large tensile strain of 100% or under a high pressure of 2000 kPa. Meanwhile, the capacitance of the device was maintained very well after 500 complete bending cycles, indicating that the robust gel polymer endows the fabricated AEESC with good flexibility and electrochemical stability.

The effective polymerization process is very desirable in the field of macromolecule science. In this study, we present a facile synthetic method via aldol addition and condensation (AAC) that leads to the formation of fluorescent linear and branched polymers by cross coupling triphenylamines (TPA) and cyclohexanones (CYC) via CC bond formation. The methodology has the advantage of easy operations, mild reaction conditions, and high yield. Via the analysis of NMR, FT-IR, GPC, PL, UV, SEM, and theoretical calculation, the structure, physical properties, and optical behaviors of both polymers were well-characterized. The understanding of cell transplantation, migration, division, fusion, and lysis is a very challenging task. In this study, the linear polymer (LP) exhibits excellent biocompatibility and low cytotoxicity, which can be readily internalized by living cells in a noninvasive manner. The images of MPC5 cells indicate that LP can be a promising emissive fluorescence probe for bioimaging application.

H3+xPMo12−xVxO40@MIL-100 (Fe) (x = 0, 1, 2) hybrids were prepared by encapsulation of polyoxometalates (POMs) within a metal–organic framework using a direct hydrothermal method. The as-prepared samples were well characterized by X-ray diffraction (XRD), Fourier transform infrared spectrophotometry (FT-IR), transmission electron microscopy (TEM), N2 adsorption–desorption, UV-vis diffused reflectance spectra and inductively coupled plasma atomic emission spectrometry (ICP-AES) analysis. The catalytic performances of the samples were tested in the oxidation of cyclohexene using H2O2 as green oxidant. The results have shown that both H4PMo11VO40@MIL-100 (Fe) and H5PMo10V2O40@MIL-100 (Fe) can effectively catalyze the allylic oxidation of cyclohexene to give 2-cyclohexen-1-one as the main product. In particular, when H4PMo11VO40@MIL-100 (Fe) was employed, 85% cyclohexene conversion, 91% selectivity for 2-cyclohexene-1-one and 715 h−1 of turnover frequency were obtained under optimized conditions. The catalyst can be reused at least five times without obvious loss of activity.

A novel and high-performance foldable solid-state supercapacitor has been developed based on nitrogen-containing polyaniline-based carbon nanosphere (C-PANI) coated carbon cloth electrodes and the AQSA-Na (anthraquinone-2-sulfonic acid sodium salt) redox mediator doped PVA (polyvinyl alcohol)–H2SO4 robust gel film electrolyte. The foldable solid-state supercapacitor demonstrates outstanding electrochemical performance such as a large specific capacitance of 430 F g−1 at a current density of 0.8 A g−1, a remarkably high energy density of 33.4 W h kg−1 at a power density of 600 W kg−1 and excellent cycling stability with 90% specific capacitance retention after 1000 cycles. Simultaneously, the high flexibility of the as-fabricated solid-state supercapacitor enabled it to work under both normal and folding conditions, and the device could be folded/unfolded repeatedly up to 500 times with only a small capacitance loss of 9%. These results indicate that the as-fabricated solid-state supercapacitor is suitable for highly fold-tolerant high-energy-density energy storage device applications. More importantly, owing to the solid-state and integrated configuration, several supercapacitors can be conveniently interconnected together in series or parallel to improve the output potential or current.

A series of MIL-53(Fe)-graphene nanocomposite photocatalysts were synthesized by a facile one-pot solvothermal reaction. All materials have been thoroughly characterized by FT-IR, SEM, TEM, PXRD, UV–vis DRS and PL analysis. It was demonstrated that the introducing of graphene on the MIL-53(Fe) would minimize the recombination of photogenerated electron-hole pairs, thus, leading to the enhancement of photocatalytic activity. MIL-53(Fe)-graphene nanocomposite was an efficient catalyst towards the photocatalytic selectively oxidation of alcohols to the corresponding aldehydes or ketones under visible light and ambient conditions. High selectivity of the aldehydes or ketones (99%) were obtained. Meanwhile, the catalyst can be recycled at least four times without loss of catalytic efficiency. A possible photocatalytic reaction mechanism involving a direct photogenerated hole-oxidation process was also investigated in detail by the active species trapping experiments and the related electrochemical analysis.

The use of heteroatom-doped carbon materials in the oxygen reduction reaction (ORR) continues to be an attractive alternative to Pt-based catalyst. In this work, nitrogen and sulfur dual self-doped hierarchically micro- and mesoporous graphitic carbon catalyst was prepared by pyrolysis of methyl orange (Fe (III)) complex, followed by removing the metal species in acid. The catalyst shows high electrocatalytic activity, long-term stability and tolerance for methanol in both acidic and alkaline media. Especially, the catalyst exhibits superior ORR electrocatalytic activity than that of the commercial Pt/C (20 wt %) in 0.1 M KOH: 0.962 and 0.865 V (vs RHE) of onset and half-wave potential was obtained, which is 8/22 mV positive than that for Pt/C, respectively. Additionally, the catalyst exhibits much greater stability than Pt/C. Kinetics investigations show that the catalyst follows the efficient 4-electron pathway for ORR in both the alkaline and acidic electrolyte.

Metal-organic frameworks (MOFs) offer great advantages for construction of bimetallic alloys as efficient oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) electrocatalysts for rechargeable/flexible Zn-air batteries. Herein, a template-assisted method is developed to reduce the crystal size of CoFe-ZIF via in-situ growing on hollow polypyrrole spheres (h-PPy). As a result, the well-dispersed ultrafine CoFe nanoalloy were obtained with N-doped hollow carbon microspheres (N-HCSs) as support. Owing to the unique alloy structure with ultrafine size, uniform dispersion of the CoFe nanoalloy on the highly conductive N-HCSs support via strong interactions, the proposed CoFe/N-HCSs afford high catalytic activity and stability toward ORR. Interestingly, the CoFe/N-HCSs also deliver a low overpotential of 292 mV at 10 mA cm−2 for OER in alkaline electrolyte, demonstrating their superior bifunctional catalytic performance. Moreover, the CoFe/N-HCSs can endow the liquid Zn-air batteries with better energy density (882.3 Wh kgZn−1) and cycling stability than those of Pt/C catalyst and exhibit potential feasibility in all-solid-state Zn-air batteries.