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Abstract Development of high-performance electrocatalysts for overall water splitting is vital for the production of renewable hydrogen energy. Monolithic Ni(OH) 2 nanosheets are fabricated through a facile hydrothermal oxidation procedure of commercial Ni foam. And Ni 2 P, Ni 2 S 3 and NiSe 2 nanosheets are obtained by subsequent low-temperature phosphorization, sulfurization and selenization of the monolithic Ni(OH) 2 nanosheets, respectively. The resultant monolithic materials can be directly employed as self-supported electrodes for efficient oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) in alkaline media, especially, Ni(OH) 2 nanosheets for OER and Ni 2 P nanosheets for HER, respectively, revealing their versatile and practical nature for hydrogen production. Moreover, a well water electrolyzer through a matched electrode pair with Ni(OH) 2 nanosheets as anode and Ni 2 P nanosheets as cathode can achieve a water splitting current density of 10 mA cm−2 at a cell voltage of 1.64 V, and maintains this current density as least 48 h without evident decay in 1.0 mol L−1 KOH electrolyte. These efficient electrocatalysts with a low-cost, facile synthesis procedure and additive-free properties have great potential for emerging realistic energy storage and conversion fields. Graphical abstract A facile strategy was developed for the fabrication of monolithic Ni x M y (M = OH, P, S, Se) nanosheets on Ni foam with integrated configuration. The resultant materials as self-supported electrodes exhibit significant activity and durability for efficient oxygen/hydrogen evolution reactions. Image 1 [ABSTRACT FROM AUTHOR]

The rapid growth of environment pressures and fast depletion of fossil fuels compel public to pay more attention on developing affordable and efficient catalysts for renewable energy production. Metal (Co, Fe, Ni, etc.) phosphide nanoparticles uniformly encapsulated in porous N,P-codoped nanofibrous carbon coated on carbon paper (MeP@NPC/CP) are prepared through one-pot carbonization-phosphorization strategy, which are potential for effective electrocatalytic water reduction/oxidation reactions. The well-designed self-supported structure and the abundant accessible active centers together contribute to the high electrocatalytic performance for hydrogen and oxygen evolution. Remarkably, an alkaline electrolyzer assembled from CoP@NPC/CP as cathode and anode can afford the current density of 10 mA cm −2 at the voltage of 1.67 V for overall water splitting in alkaline media with excellent stability. The easily prepared route with suitable structural and textural properties endows this self-supported materials with versatile function as abundant metal catalysts for realistic energy conversion and storage systems. [ABSTRACT FROM AUTHOR]

• Abundant heterostructure interfaces are formed in CoFe/CoFe 2 O 4 nanoparticles on N,P-doped porous carbon. • Waste biomass tobacco derived electrocatalysts exhibit remarked bifunctional OER/ORR activity. • Rechargeable Zn-Air batteries with CoFe/CoFe 2 O 4 @PNC shows outstanding power density and durability. Bifunctional oxygen reduction/oxidation reaction (ORR/OER) electrocatalysts can be derived from waste biomass for implementing rechargeable Zn–air batteries, which not only turns waste into wealth, but also provides a novel approach for solving the energy crisis and promoting environmental restoration. Herein, heterostructured CoFe/CoFe 2 O 4 nanoparticles grown on waste tobacco-derived N,P-co-doped carbon (CoFe/CoFe 2 O 4 @PNC) are constructed. Benefiting from the accelerated electron transfer due to the synergistic effect of CoFe and CoFe 2 O 4 along with the enlarged active area owing to N,P-codoping, the CoFe/CoFe 2 O 4 @PNC electrocatalysts exhibit remarkable OER/ORR activity, reaching a half-wave potential of 0.86 V for ORR solution and driving 10 mA cm−2 by OER overpotential of 360 mV in 1.0 M KOH. Moreover, the zinc-air battery assembled with CoFe/CoFe 2 O 4 @PNC can reach a power density of 141.5 mW cm−2 and exhibit impressive durability for exceeding 300 h, which are superior to the power density and stability of zinc-air batteries assembled with precious metal-based materials. This work opens up new possibilities for preparing advanced ORR/OER catalysts for efficient Zn-based batteries. Waste tobacco derived N, P dual-doped porous carbons loaded with heterostructured CoFe/CoFe 2 O 4 nanoparticles are fabricated for efficient oxygen electrocatalysis and Zn-air batteries [Display omitted] [ABSTRACT FROM AUTHOR]

Nanocarbon is an important metal-free catalyst for various applications including oxidative dehydrogenation and direct dehydrogenation reactions. The surface oxygen-containing groups of nanocarbon are regarded as active sites in oxidative dehydrogenation reaction. However, the active sites for direct dehydrogenation are still not totally clear. Herein, multiwall carbon nanotubes (MWCNTs) are activated by different oxidation processes and thermal treatments, and used as effective catalysts for direct dehydrogenation of propane to propylene. The physicochemical properties of the oxidized MWCNTs are characterized by SEM, TEM, XRD, N 2 sorption, Raman, TGA, TPD-MS and XPS techniques. It is revealed that the concentrations of the oxygen-containing groups could be well controlled by sequential acid oxidation and thermal treatment. The activities of these nanocarbon catalysts exhibit a good linear dependence on the number of carbonyl/quinone groups, confirming the active sites are C O groups on the surface of the MWCNTs. [ABSTRACT FROM AUTHOR]

The nature of the support for the supported heterogeneous catalysts plays a vital role in catalytic reactions, for example, oxidative desulfurization (ODS). Herein, mesoporous titanium phosphonates (MTP) with sufficient organophosphonic ligands are synthesized as the support of molybdenum oxides for ODS. The homogeneous organophosphonic ligands in MTP facilitate the effective adsorption of Mo 7 O 24 6−; after subsequent low-temperature annealing, the highly dispersed molybdenum oxides on MTP (Mo/MTP) with strong coupling effect are prepared. The electron-donating effect of organophosphonic ligands endows Mo active sites with high electron density. In addition, the mesoporous structure and large specific surface area of MTP are beneficial for improving the local concentration of reactants around the active sites. The 5%Mo/MTP-350 exhibits excellent ODS catalytic activity with 100% desulfurization in 30 min at 40 °C and robust recycling stability. This work presents a successful example for the application of MTP supported active components, and provides some inspirations for the potential applications of metal phosphonates as catalyst support in energy and environmental catalysis. The ultrafine molybdenum oxides dispersed on mesoporous titanium phosphonates are rationally prepared through the facile adsorption and annealing procedures, capable of impressive activity and recycling performance for oxidative desulfurization. Image 1 • Mesoporous Ti phosphonates (MTP) supported Mo oxide nanoparticles of high dispersion. • The fabricated Mo/MTP catalysts exhibit excellent oxidative desulfurization activity. • The strong coupling effect exists between MTP and molybdenum oxide nanoparticles. • Homogeneous organophosphonic ligands lead to highly dispersed molybdenum oxides. • The electron-donating effect of organophosphonic ligands to Mo active sites. [ABSTRACT FROM AUTHOR]