Bader Charge Balance Mechanism Realizes Industrial-Grade Current Hydrogen Production.

Abstract

The hydrogen production technology of water splitting under a high current density is the key to solve the efficient utilization of hydrogen energy. However, it is difficult for existing catalysts to exhibit bifunctional high-current activity in the same electrolyzer, considering that the bimetallic site can endow the catalytic material asymmetry and heterogeneity and then change the intrinsic electronic structure. Herein, we constructed a La-Fe dual-site coupled self-assembled membrane electrode (D-LaFe-SAME), and the introduction of the dual site reduced the Bader charge value of the La site from 0.87 to 0.83|e|, while the Bader charge of the Fe site increased from 0.69 to 0.70|e|, thus optimizing the Bader charge value of La-Fe active sites to a close equilibrium. Consequently, the free energy barrier of the rate-determining step is optimized, and the catalytic activity is greatly improved. Prominently, the optimal D-LaFe-SAME can achieve current densities of up to 2000 mA cm-2 at very low overpotentials (-640 mV for HER and 626 mV for OER), which is even better than the commercial precious metals Pt/C and IrO2. Surprisingly, when we use a large area of D-LaFe-SAME for overall water splitting, it can operate stably at currents up to 4 A. The dual-site coupled strategy based on the Bader charge balance mechanism proposed in this work is crucial for the construction of an efficient and high-current electrocatalytic system for hydrogen production in the same electrolyzer and plays a key role in achieving the goals of carbon neutrality.