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Work function strongly impacts the surficial charge distribution, especially for metal‐support electrocatalysts when a built‐in electric field (BEF) is constructed. Therefore, studying the correlation between work function and BEF is crucial for understanding the intrinsic reaction mechanism. Herein, we present a Pt@CoOx electrocatalyst with a large work function difference (ΔΦ) and strong BEF, which shows outstanding hydrogen evolution activity in a neutral medium with a 4.5‐fold mass activity higher than 20 % Pt/C. Both experimental and theoretical results confirm the interfacial charge redistribution induced by the strong BEF, thus subtly optimizing hydrogen and hydroxide adsorption energy. This work not only provides fresh insights into the neutral hydrogen evolution mechanism but also proposes new design principles toward efficient electrocatalysts for hydrogen production in a neutral medium. [ABSTRACT FROM AUTHOR]

The electrocatalyzed oxygen reduction and evolution reactions (ORR and OER, respectively) are the core components of many energy conversion systems, including water splitting, fuel cells, and metal-air batteries. Rational design of highly efficient non-noble materials as bifunctional ORR/OER electrocatalysts is of great importance for large-scale practical applications. A new strongly coupled hybrid material is presented, which comprises CoO x nanoparticles rich in oxygen vacancies grown on B,N-decorated graphene (CoO x NPs/BNG) and operates as an efficient bifunctional OER/ORR electrocatalyst. Advanced spectroscopic techniques were used to confirm formation of abundant oxygen vacancies and strong Co−N−C bridging bonds within the CoO x NPs/BNG hybrid. Surprisingly, the CoO x NPs/BNG hybrid electrocatalyst is highly efficient for the OER with a low overpotential and Tafel slope, and is active in the ORR with a positive half-wave potential and high limiting current density in alkaline medium. [ABSTRACT FROM AUTHOR]

Rational design of non-noble materials as highly efficient, economical, and durable bifunctional catalysts for oxygen evolution and reduction reactions (OER/ORR) is currently a critical obstacle for rechargeable metal-air batteries. A new route involving S was developed to achieve atomic dispersion of Fe-N x species on N and S co-decorated hierarchical carbon layers, resulting in single-atom bifunctional OER/ORR catalysts for the first time. The abundant atomically dispersed Fe-N x species are highly catalytically active, the hierarchical structure offers more opportunities for active sites, and the electrical conductivity is greatly improved. The obtained electrocatalyst exhibits higher limiting current density and a more positive half-wave potential for ORR, as well as a lower overpotential for OER under alkaline conditions. Moreover, a rechargeable Zn-air battery device comprising this hybrid catalyst shows superior performance compared to Pt/C catalyst. This work will open a new avenue to design advanced bifunctional catalysts for reversible energy storage and conversion devices. [ABSTRACT FROM AUTHOR]

Developing highly active catalysts for the oxygen evolution reaction (OER) is of paramount importance for designing various renewable energy storage and conversion devices. Herein, we report the synthesis of a category of Co-Pi analogue, namely cobalt-based borate (Co-Bi) ultrathin nanosheets/graphene hybrid by a room-temperature synthesis approach. Benefiting from the high surface active sites exposure yield, enhanced electron transfer capacity, and strong synergetic coupled effect, this Co-Bi NS/G hybrid shows high catalytic activity with current density of 10 mA cm−2 at overpotential of 290 mV and Tafel slope of 53 mV dec−1 in alkaline medium. Moreover, Co-Bi NS/G electrocatalysts also exhibit promising performance under neutral conditions, with a low onset potential of 235 mV and high current density of 14.4 mA cm−2 at 1.8 V, which is the best OER performance among well-developed Co-based OER electrocatalysts to date. Our finding paves a way to develop highly active OER electrocatalysts. [ABSTRACT FROM AUTHOR]

Designing highly efficient electrocatalysts for oxygen evolution reaction (OER) plays a key role in the development of various renewable energy storage and conversion devices. In this work, we developed metallic Co4Nporous nanowire arrays directly grown on flexible substrates as highly active OER electrocatalysts for the first time. Benefiting from the collaborative advantages of metallic character, 1D porous nanowire arrays, and unique 3D electrode configuration, surface oxidation activated Co4N porous nanowire arrays/carbon cloth achieved an extremely small overpotential of 257 mV at a current density of 10 mAcm-2, and a low Tafel slope of 44 mVdec-1 in an alkaline medium, which is the best OER performance among reported Co-based electrocatalysts to date. Moreover, in-depth mechanistic investigations demonstrate the active phases are the metallic Co4N core inside with a thin cobalt oxides/hydroxides shell during the OER process. Our finding introduces a new concept to explore the design of highefficiency OER electrocatalysts. [ABSTRACT FROM AUTHOR]

Metallic Co4N porous nanowire arrays are grown on carbon fabrics (CF) by nitriding CF-supported Co(OH)F nanowires (420 °C, 2 h). [ABSTRACT FROM AUTHOR]

Pristine Ca0.9Yb0.1MnO3 is prepared by calcination of a stoichiometric mixture of Yb2O3, CaCO3, and MnO2 in air (staged heating to 1300 °C, 24 h). [ABSTRACT FROM AUTHOR]