Electronic structure modulation of MoO2 via Er-doping for efficient overall water/seawater splitting and Mg/seawater batteries
Teng Yang, Honghao Lv, Qinghao Quan, Xiaolei Li, Huasen Lu, Xuejing Cui, Guangbo Liu, Luhua Jiang
Abstract
Electronic structure modulation is an effective strategy for electrocatalysts to boost their hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) activities in water splitting. Here, a rational design of rare earth element Er-doped MoO 2 (Er-MoO 2 ) with modulated electronic structure is reported, leading to boosted water splitting activity in both alkaline and seawater electrolyte. Experimental results manifest that the optimized Er-MoO 2 requires overpotentials of only 94/221 mV and 173/312 mV to deliver the 10 mA cm −2 for HER/OER in alkaline and seawater electrolyte, respectively. As bifunctional electrocatalysts for overall water splitting, the Er-MoO 2 requires a cell voltage of only 1.52 and 1.67 V to gain 10 mA cm −2 in alkaline and seawater electrolyte, respectively. Moreover, a Mg/seawater battery coupled with the Er-MoO 2 cathode achieves a maximum power density of 8.17 mW cm −2 , combining with an excellent discharging stability for at least 24 h. This work provides a facile strategy toward the design of efficient non-noble metal catalysts for overall water/seawater splitting and Mg/seawater battery.