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Three kinds of Pt nanocrystals with different morphologies (5 nm cubes, 10 nm cubes and 5 nm truncated octahedrons) were synthesized and employed to fabricate Pt/CNT-USY catalysts for selective ring opening of decalin. The 5 nm truncated octahedral Pt/CNT-USY with exposed (100) and (111) facets exhibited higher yield of ring-opening products (53.9 wt%) than the CNT-USY-supported 5 nm cubic Pt catalyst enclosed by the (100) facets (39.6 wt%). Moreover, the 5 nm cubic Pt showed better catalytic activities compared to the 10 nm cubic Pt/CNT-UST catalyst, which ascribed to the smaller size of Pt NCs enriched more revealable metal active sites. DFT calculations demonstrated that the adsorption of decalin on Pt (111) was stronger than that on Pt (100) facets, which was profitable for the selective ring-opening reaction. [ABSTRACT FROM AUTHOR]

[Display omitted] • One-pot Solvent-free Synthesis strategy is proposed to prepare polycycloalkanes. • Novel NbOPO 4 nanosheets were fabricated to integrate alkylation and HDO processes. • Accessible Brønsted acidic sites of NbOPO 4 nanosheet favors alkylation. • Cocatalysts of NbOPO 4 and Ru/C accelerate the hydrodeoxygenation rate. • A renewable fuel of perhydrofluorene and dicyclohexylmethane was selectively prepared. Upgrading lignocellulose biomass to renewable fuels is essential to achieve carbon neutrality. However, the multiple synthetic, and purification steps as well as the employment of solvents in the production of renewable fuel inhibit the overall yields and cause the waste of energy and resources. Herein, a new catalytic strategy for one-pot solvent-free sequential synthesis (OSS) of perhydrofluorene and dicyclohexylmethane was developed from lignin-derivatives. A two-dimensional layered nanosheet niobium phosphate (NbOPO 4 -IB) catalyst was fabricated to efficiently integrate the alkylation of phenol and benzyl alcohol and sequential hydrodeoxygenation with a cocatalyst of Ru/C. The high crystalline NbOPO 4 phase and the lamellar morphology contributes to the large specific surface area to expose more active sites, especially more Brønsted acid sites. The NbOPO 4 -IB catalyst with a suitable Brønsted/Lewis acid ratio of 1.49 favors the selectivity of fuel precursors benzyl phenol in the alkylation and also provides the appropriate acid strength to promote hydrodeoxygenation activity. NbOPO 4 -IB also shows good reusability. Excessive phenol plays a vital role in promoting the alkylation reaction by dissolving the intermediates, and then into cyclohexane to enhance the H 2 dissolution in the hydrodeoxygenation. A possible mechanism of OSS from lignin-derivatives into polycycloalkanes over the cocatalysts was proposed. [ABSTRACT FROM AUTHOR]

[Display omitted] • IrCo 0.13 nanoalloy is prepared by chemical reduction and electrochemical treatment. • Abundant Co vacancies and atomic heterostructure facilitate OER and HER. • Strong interaction of Ir and Co contributes to remarkable stability and activity. • IrCo 0.13 exhibits an overpotential of 238 (OER) and 18.6 mV (HER)@10 mA cm−2, respectively. • Bifunctional IrCo 0.13 as both anode and cathode displays 1.68 V@1 A cm−2 in PEMWE. Exploring the electrocatalysts with high intrinsic activity and stability for both anode and cathode to tolerate the extremely acidic condition in proton exchange membrane water electrolyzer (PEMWE) is crucial for widespread industrial application. Herein, we constructed the bifunctional IrCo x nanoalloys with abundant metal vacancies via the combination of chemical reduction and electrochemical treatment for overall water splitting. The developed IrCo 0.13 exhibits ultra-low overpotentials of 238 mV for OER and 18.6 mV for HER at 10 mA cm−2 in 0.1 M HClO 4 , and achieves the exceptional stability of 1000 h for OER and 100 h for HER at 10 mA cm−2. Further, the cell voltage is only 1.68 V to reach a high current density of 1 A cm−2 in PEMWE with IrCo 0.13 as the both cathode and anode catalytic layer, and it shows excellent corrosion resistance in acidic environment, evidenced by 415 h stable operation at 1 A cm−2. The strong electronic interactions in the Ir-Co atomic heterostructure and the in-situ generation of Co vacancies by electrochemical oxidation synergistically contribute to the enhanced activity and stability via optimizing the electronic structure of adjacent Ir active sites, enhancing the conductivity and electrochemical active surface area of the catalyst, accelerating charge transfer and kinetics. This work provides a new perspective for designing bifunctional catalysts for practical application in PEMWE. [ABSTRACT FROM AUTHOR]

Selective deep hydrosaturation of polyaromatics has attracted significant attention in reinforcing the utilization of heavy resources and decreasing the emission of harmful particulate matters. Herein, supported Pt catalysts on diverse oxide supports (SiO 2 , TiO 2 , CeO 2) were prepared using an enhanced strong electrostatic adsorption tactics. Strong electronic metal-support interactions (EMSI) in Pt/TiO 2 and Pt/CeO 2 leaded to the well-dispersed electron-deficient Ptδ+ substances and intensified hydrogen spillover capacity, where the most Ptδ+ and spillover hydrogen were acquired on Pt/CeO 2 ascribed to the maximal EMSI and lower oxygen vacancy formation energy heightened the adsorption of metallic Pt. Moreover, the Ptδ+ species displayed promoted H 2 dissociation ability and boosted adsorption energy for aromatic. In phenanthrene hydrogenation, Pt/TiO 2 presented better activity and selectivity to deep hydrosaturation products than Pt/SiO 2 catalyst, indicating the enhancement of EMSI in hydrogenation. Meanwhile, the catalytic properties were further improved over Pt/CeO 2 exhibiting the highest rate of 3.63 × 10−4 mol·kg−1·s−1. It delivered almost 100% conversion and selectivity to deep hydrogenation at 220 °C because of the maximal of Ptδ+ species with superb dispersion and hydrogen spillover. Furthermore, the DFT calculations manifested the enhanced adsorption of aromatic on Ptδ+ species promoting deep hydrogenation. [Display omitted] • Enhanced strong electrostatic adsorption method was employed to prepare Pt catalysts. • Strong electronic metal-support interaction motivated the dispersion of supported metal. • Oxygen vacancies in reducible supports promoted electronic metal-support interaction. • Electron-deficient Ptδ+ and spillover hydrogen could facilitate aromatic deep hydrogenation. • The Pt/CeO 2 catalyst exhibited the best deep hydrosaturation properties for polyaromatic. [ABSTRACT FROM AUTHOR]

[Display omitted] • The hollow hierarchical ZSM-5 supported Pt catalyst was synthesized by SEA method. • SEA can boost metal dispersion and formation of electron-deficient Ptδ+ species. • The Ptδ+ species combing acidic sites presented excellent deep hydrogenation ability. • DFT calculations confirmed that the Ptδ+ species can enhance the adsorption of PAHs. • Pt/HZ-SEA showed excellent PHE intrinsic hydrogenation activity and sulfur-resistant. Deep hydrogenation of polycyclic aromatic hydrocarbons is a feasible strategy to acquire high-performance aviation fuels, in which the key is to design highly active hydrogenation catalysts. Herein, hollow ZSM-5 (HZ) and silicalite-1 (HS) zeolites with hierarchical porous architectures were manufactured through a post-alkali treatment strategy, and further supported Pt to fabricate Pt/HZ-WI, Pt/HZ-SEA and Pt/HS-SEA catalysts employing wet impregnation (WI) and strong electrostatic adsorption (SEA) methods. The SEA catalysts presented higher metal dispersion, more election-deficient Ptδ+ species and stronger spillover hydrogen ability, thus resulting in better intrinsic hydrogenation properties in the deep hydrogenation reaction of phenanthrene than the WI ones. Moreover, Pt/HZ-SEA catalyst showed the supreme catalytic activity and the lowest activation energy of 52.11 kJ·mol−1 due to more hydrogenation active sites generated by the highly dispersed Pt clusters and the accelerated diffusion of reactants via the hierarchical porous architectures. Almost 100% selectivity to the deep hydrogenation products was achieved at rather low temperature of 220 °C. The Pt/HZ-SEA also displayed outstanding activity for hydrogenation of naphthalene, acenaphthylene and fluorene and excellent sulfur resistance. Furthermore, the acidic sites in HZ zeolite were favorable to boost the formation of electron-deficient Ptδ+ species having stronger deep hydrogenation ability and intensify the additional hydrogenation route through the spillover hydrogen. Finally, the DFT calculation results further verified that the Ptδ+ substances could heighten the adsorption of polyaromatics, thereby improving the deep hydrogenation activity. [ABSTRACT FROM AUTHOR]

Ni/ZSM-5 nanosheet catalysts with different Si/Al ratios were modified by chemical liquid deposition (CLD) of tetraethoxysilane (TEOS) to tailor their acid spatial distribution. Their catalytic performance was evaluated with the hydroconversion of oleic acid to aviation-fuel-range-alkanes (AFRAs) at different reaction temperatures and H 2 pressures. The modified catalysts inherit the nanosheet structure with decreased external Brønsted acid concentration, especially the strong one. External Brønsted acid sites mainly favor the cracking of the deoxygenated products (C 17 /C 18). Internal Brønsted acid sites mainly enhance the isomerization of the linear AFRAs. And the catalytic activity of the external Brønsted acid sites was more sensitive to reaction temperature than that of the internal ones. The deoxygenation and cracking reactions were also more sensitive to H 2 pressure compared to the isomerization reaction. High AFRA selectivity of 51.4% as well as high iso/n -alkanes ratio of 1.7 were achieved at 250 °C and 10 bar over NS200(1). Image 1 • CLD tailors external acid sites with similar pore structures and Ni distributions. • External B acid sites mainly favor the cracking of the deoxygenated products. • Internal B acid sites mainly enhance the isomerization of the linear AFRAs. • Cracking reaction is more sensitive to temperature and pressure than isomerization. • A high AFRA selectivity of 51.4% with high iso/n -alkanes ratio of 1.7 is achieved. [ABSTRACT FROM AUTHOR]

Hollow Silicalite-1 and ZSM-5 zeolites with hierarchical porous shells have been synthesized by using a dissolution-recrystallization method. The morphology, structure, and acidity of these zeolites supported Pt catalysts were characterized by XRD, FT-IR, MAS-SSNMR, FE-SEM, FE-TEM, N2-BET, XPS, NH3-TPD, and CO pulse chemisorption. Compared to the conventional ZSM-5 supported Pt catalyst, the special structure in hollow ZSM-5 zeolite significantly promotes the dispersion of metallic Pt and the synergistic effect between metal active sites and acid sites. These boost the catalytic activity, selectivity of guaiacol hydrodeoxygenation toward cycloalkanes and long-term stability over the Pt/hollow ZSM-5 catalyst combined with improved mass transfer of products and reactants derived from the hierarchical hollow porous structure. Moreover, the Pt/hollow ZSM-5 catalyst exhibits excellent low temperature catalytic activity to completely transform guaiacol into cycloalkanes with the cyclohexane selectivity of more than 93% at 220 °C, suggesting that hollow ZSM-5 zeolite is a promising support for upgrading of bio-oils. [ABSTRACT FROM AUTHOR]

[Display omitted] • The metal-acid sites intimacy was regulated by strong electrostatic adsorption. • Hydroisomerization and hydrocracking mechanisms were altered via tailoring the metal-acid sites intimacy. • Nanoscale metal-acid sites intimacy reduced acid steps (n as). • The isomerization selectivity showed a linear decease with the increase of n as values. • Fewer acid steps were beneficial to the pore mouth mechanism. Designing a bifunctional catalyst to achieve efficient hydroisomerization of long-chain alkanes is very essential for producing high-performance fuel and lubricant base oils. Herein, a bifunctional catalyst composed of an intimate mixture of ZSM-48 zeolite and alumina binder and with platinum (Pt) metal controllably deposited on zeolite or alumina was fabricated by a strong electrostatic adsorption method. The dependence of reaction pathways of hydroisomerization and hydrocracking of n -hexadecane on the metal-acid sites intimacy was investigated. High Brønsted acid density and suitable metal-acid sites intimacy favored to promote the catalytic activity. The selectivity, hydroisomerization mechanism and hydrocracking mechanism were significantly altered by tailoring the metal-acid sites intimacy. Too large or too small metal-acid sites intimacy was conducive to inhibit the occurrence of pore-mouth mode. A linear decease of the hydroisomerization selectivity with the increase of acid steps (n as) was observed. The catalyst with nanoscale intimacy of metal-acid sites (Pt/A-48) showed the highest catalytic activity and isomer selectivity (87%) and the least acid steps (n as = 1.4). This work provides a promising approach to fabricating highly efficient and shape-selective bifunctional catalysts for selective hydroisomerization of long-chain alkanes. A reaction network was proposed over the catalysts with different metal-acid intimacy. [ABSTRACT FROM AUTHOR]

Developing highly selective and efficient bifunctional catalysts is an important issue for the hydroisomerization of long-chain n-alkanes. It is vital to tailor the balance of isomerization and cracking reactions in hydroisomerization. Herein, a bifunctional Pt/hierarchical SSZ-32 catalyst was fabricated with a sequential desilication–dealumination treatment to boost the selective hydroisomerization of n-hexadecane (C16). The pore structure and acid sites of SSZ-32 zeolite were tailored. More mesopore and Brønsted acid sites were generated, and the ratio of weak to strong Brønsted acidity (Bw/Bs) was increased by the sequential desilication–dealumination. The generated hierarchical structure had little effect on the selectivity of the reaction pathways of hydroisomerization versus cracking. The ratio of isomers/cracking products increased almost linearly with the increase in the Bw/Bs ratios. Meanwhile, the synergetic effect of the hierarchical structure and acidity regulation promoted the selectivity of monobranched i-C16 products. Therefore, the resulting Pt/SSZ-0.6AS exhibited the highest activity with a total isomer yield of 71.5% at 255 °C and the enhanced formation mechanism of monobranched isomers occurred via the pore mouth. [ABSTRACT FROM AUTHOR]

• Hollow IrCoO x structure is fabricated via a sample in-situ reconstruction strategy. • The unique hollow structure exposes more active sites and increases the active area. • The IrO x -rich shell is enriched in crystalline/amorphous and atomic heterointerface. • Hollow structure and heterointerface are beneficial to improve OER performance. • Hollow Ir 0.16 Co 0.84 O x presents excellent mass activity of 1032.16 A g Ir -1. Iridium oxide (IrO x)-based materials perform high efficiency and durability for oxygen evolution reaction (OER) in acidic environment. Developing highly efficient OER electrocatalysts with low Ir-loading in acid is still a great challenge. Herein, we fabricated a hollow IrCoO x nanosphere via in-situ electrochemistry reconstruction strategy. The developed hollow Ir 0.16 Co 0.84 O x electrocatalyst with low Ir-loading (51.91 μg cm−2) exhibits 71-fold and 42-fold improvement in OER mass activity and TOF value compared with commercial IrO 2 (1032.16 vs 14.44 A g Ir −1, 0.754 vs 0.018 s−1) in 0.1M HClO 4 , respectively. Combining with the analysis of the IrCoO x structure, the electrochemical performance reveals that the superior activity ascribes to the favorable hollow structure, the abundant crystalline/amorphous heterostructure in the IrO x -enriched shell and the atomic heterointerfaces between Co and Ir oxides, which increase the electrochemical active area, accelerate the OER kinetics and lower the charge transfer resistance (2.8 Ω cm2). This work is anticipated to aid the design of novel low Ir-loading electrocatalysts with outstanding catalytic activity for water splitting in acidic environments. [Display omitted] [ABSTRACT FROM AUTHOR]

Electrochemical valorization of non‐food biomass‐derived carboxylates into fuels is promising for the conversion, storage, and distribution of renewable electricity. Herein, we demonstrate that biofuels, hydrogen, and bicarbonate can be simultaneously produced in an electrochemical cell by one‐step electrolysis of free fatty acids under ambient conditions on 3D self‐supported ultralow Pt loading (2 wt %) electrode. The three valuable products can naturally separate from each other during the electrolysis in the alkaline aqueous solution. The experimental suggests that Pt(100) and Pt(110) are favorable for the production of non‐Kolbe and Kolbe hydrocarbons, respectively. DFT calculation further clarifies the adsorption and stabilization of the reaction intermediates on Pt(100) and Pt(110). [ABSTRACT FROM AUTHOR]

• A novel electrodeposition method is developed to prepare self-supported amorphous IrO x /Ti electrode. • Pre-activation plays a significant role in in-situ constructing an amorphous film. • The amorphous IrO x film exposes high contents of active IrIII species and surface hydroxides to enhance the OER performance. • Amorphous-crystalline synergy and rich interface contribute to the superior stability and activity. • A super durability for 190 h at 10 mA cm−2 and 50 mA cm−2 was achieved for amorphous IrO x -50/Ti. Developing highly active and stable electrocatalysts for acidic oxygen evolution reaction is still a great challenge. Herein, we developed a novel self-supported amorphous IrO x catalyst (IrO x /Ti) encapsulated with a small number of crystalline nanoparticles for efficient acidic OER. The resulting IrO x -50-AC/Ti electrode exhibits a superior OER performance with an overpotential of 250 mV at 10 mA cm−2 and Tafel slope of 50.4 mV dec−1 in 0.1 M HClO 4. High contents of IrIII species and surface hydroxide groups, hierarchically porous structure and high defective density contribute to boost the OER activity. Importantly, the amorphous IrO x -50-AC/Ti also demonstrates a super long-term durability for 190 h due to the strong interaction between IrO x film and Ti. The unique amorphous-crystalline structure also enhances the stability and the activity by promoting the synergy between amorphous phase and crystalline phase. This work provides some valuable insights on developing efficient Ir-based catalysts for acidic water splitting. [Display omitted] A novel self-supported amorphous IrO x catalyst (IrO x /Ti) is developed by an electrodeposition strategy for efficient acidic OER. The optimized amorphous IrO x -50-AC/Ti demonstrates a super long-term durability for 190 h and an excellent activity with an overpotential of 250 mV to obtain 10 mA cm−2 in 0.1 M HClO 4. [ABSTRACT FROM AUTHOR]

The copper-based catalyst is considered to be the only catalyst for electrochemical carbon dioxide reduction to produce a variety of hydrocarbons, but its low selectivity and low current density to C2 products restrict its development. Herein, a core-shell xZnO@yCu2O catalysts for electrochemical CO2 reduction was fabricated via a two-step route. The high selectivity of C2 products of 49.8% on ZnO@4Cu2O (ethylene 33.5%, ethanol 16.3%) with an excellent total current density of 140.1 mA cm−2 was achieved over this core-shell structure catalyst in a flow cell, in which the C2 selectivity was twice that of Cu2O. The high electrochemical activity for ECR to C2 products was attributed to the synergetic effects of the ZnO core and Cu2O shell, which not only enhanced the selectivity of the coordinating electron, improved the HER overpotential, and fastened the electron transfer, but also promoted the multielectron involved kinetics for ethylene and ethanol production. This work provides some new insights into the design of highly efficient Cu-based electrocatalysts for enhancing the selectivity of electrochemical CO2 reduction to produce high-value C2 products. [ABSTRACT FROM AUTHOR]