Synergistically boosting the elementary reactions over multiheterogeneous ordered macroporous Mo2C/NC-Ru for highly efficient alkaline hydrogen evolution

Simultaneously enhancing the reaction kinetics,mass transport,and gas release during alkaline hydrogen evolution reaction(HER)is critical to minimizing the reaction polarization resistance,but remains a big challenge.Through rational design of a hierarchical multiheterogeneous three-dimensionally(3D)ordered macroporous Mo_(2)C-embedded nitrogen-doped carbon with ultrafine Ru nanoclusters anchored on its surface(OMS Mo_(2)C/NC-Ru),we realize both electronic and morphologic engineering of the catalyst to maximize the electrocatalysis performance.The formed Ru-NC heterostructure shows regulative electronic states and optimized adsorption energy with the intermediate H*,and the Mo_(2)C-NC heterostructure accelerates the Volmer reaction due to the strong water dissociation ability as confirmed by theoretical calculations.Consequently,superior HER activity in alkaline solution with an extremely low overpotential of 15.5 mV at 10 mAcm^(−2)with the mass activity more than 17 times higher than that of the benchmark Pt/C,an ultrasmall Tafel slope of 22.7 mV dec−1,and excellent electrocatalytic durability were achieved,attributing to the enhanced mass transport and favorable gas release process endowed from the unique OMS Mo_(2)C/NC-Ru structure.By oxidizing OMS Mo_(2)C/NC-Ru into OMS MoO_(3)-RuO_(2)catalyst,it can also be applied as efficient oxygen evolution electrocatalyst,enabling the construction of a quasi-symmetric electrolyzer for overall water splitting.Such a device's performance surpassed the state-of-the-art Pt/C||RuO2 electrolyzer.This study provides instructive guidance for designing 3D-ordered macroporous multicomponent catalysts for efficient catalytic applications.

Surface reconstruction establishing Mott-Schottky heterojunction and built-in space-charging effect accelerating oxygen evolution reaction

Structural reconstruction of nanomaterials offers a fantastic way to regulate the electronic structure of active sites and promote their catalytic activities.However,how to properly facilitate surface reconstruction to overcome large overpotential that stimulate the surface reconstruction has remained elusive.Herein,we adopt a facile approach to activate surface reconstruction on Ni(OH)_(2) by incorporating F anions to achieve electro-derived structural oxidation process and further boost its oxygen evolution reaction(OER)activity.Ex situ Raman and X-ray photoemission spectroscopy studies indicate that F ions incorporation facilitated surface reconstruction and promotes the original Ni(OH)_(2)transformed into a mesoporous and amorphous F-NiOOH layer during the electrochemical process.Density functional theory(DFT)calculation reveals that this self-reconstructed NiOOH induces a space-charge effect on the p-n junction interface,which not only promotes the absorption of intermediates species(^(*)OH,^(*)O,and^(*)OOH)and charge-transfer process during catalysis,but also leads to a strong interaction of the p-n junction interface to stabilize the materials.This work opens up a new possibility to regulate the electronic structure of active sites and promote their catalytic activities.