Electronic structure modulation of MoO2 via Er-doping for efficient overall water/seawater splitting and Mg/seawater batteries

• Published in: Applied surface science 2023-04, Vol.615, p.156360, Article 156360
• Main Authors: Yang, Teng, Lv, Honghao, Quan, Qinghao, Li, Xiaolei, Lu, Huasen, Cui, Xuejing, Liu, Guangbo, Jiang, Luhua
• Format: Article
• Language: English
• Subjects: Electronic structure; Er-doping; Mg/seawater battery; MoO2; Seawater splitting
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2023.156360

Er-MoO2 with modulated electronic structure was successfully fabricated via a facile method. The obtained Er-MoO2 exhibits superior overall seawater splitting, achieving a cell voltage of 1.67 V at 10 mA cm−2. A Mg/seawater battery fabricated with the Er-MoO2 cathode displaying a peak power density of 8.17 mW cm−2 and an excellent discharge stability. [Display omitted] •Demonstration of a rational design of Er-MoO2 with modulated electronic structure.•Optimized Er-MoO2 demonstrates superior overall water/seawater splitting performances.•Er-MoO2 delivers a cell voltage of 1.67 V at 10 mA cm−2 for overall seawater splitting.•Mg/seawater battery with Er-MoO2 cathode achieves a peak power density of 8.17 mW cm−2. 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 MoO2 (Er-MoO2) 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-MoO2 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-MoO2 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-MoO2 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.