Synergistically boosting the elementary reactions over multiheterogeneous ordered macroporous Mo<sub>2</sub>C/NC‐Ru for highly efficient alkaline hydrogen evolution
Kaixi Wang, Shuo Wang, Kwan San Hui, Haixing Gao, Duc Anh Dinh, Cheng‐Zong Yuan, Chenyang Zha, Zongping Shao, Zikang Tang, Kwun Nam Hui
Abstract
Abstract 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 mA cm −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 || RuO 2 electrolyzer. This study provides instructive guidance for designing 3D‐ordered macroporous multicomponent catalysts for efficient catalytic applications.