Ru/NC heterointerfaces boost energy-efficient production of green H2 over a wide pH range
Qifeng Yang, Botao Zhu, Feng Wang, Cunjin Zhang, Jiahao Cai, Peng Jin, Lai Feng
Abstract
Green hydrogen (H2) is an import energy carrier due to the zero-carbon emission in the energy cycle. Nevertheless, green H2 production based on electrolyzer and photovoltaics (EZ/PV) remains limited due to the highly pH-dependant and energy exhausting overall water splitting. Herein, we report a series of Ru-nanocluster-modified mesoporous nanospheres (Rux@mONC) as pH-universal electrocatalysts towards both hydrogen evolution reaction (HER) and hydrazine oxidation reaction (HzOR). The optimal catalyst Ru20@mONC realizes remarkable catalytic activity and stability towards both HER and HzOR regardless of electrolytes. As a result, the electrode pair of Ru20@mONC//Ru20@mONC requires low cell-potentials of 39/429, 405/926, and 164/1,141 mV to achieve the current density of 10/100 mA·cm−2, as well as the long-term stability for HzOR assisted electrochemical water splitting in alkaline, acidic, and neutral media, respectively. Those performances are more promising compared to the state-of-the-art electrocatalysts so far reported. A proof-of-concept test demonstrates an efficient production of green H2 powered by a single-junction silicon solar cell, which may inspire the use of a cost-effective EZ/PV system. Furthermore, a combined spectroscopic and theoretical study verifies the formation of abundant Ru/NC heterointerfaces in Ru20@mONC, which not only contributes to the balancing of H* adsorption/desorption in HER but also facilitates the *N2H2 dehydrogenation in HzOR.