Generating highly active oxide-phosphide heterostructure through interfacial engineering to break the energy scaling relation toward urea-assisted natural seawater electrolysis

• Published in: Journal of energy chemistry 2024-10, Vol.97, p.687-699
• Main Authors: Tran, Ngoc Quang, Vu, Nam Hoang, Yu, Jianmin, Nguyen, Khanh Vy Pham, Tran, Thuy Tien Nguyen, Truong, Thuy-Kieu, Peng, Lishan, Le, Thi Anh, Kawazoe, Yoshiyuki
• Format: Article
• Language: English
• Subjects: Break scaling relationships; Doping; Interfacial engineering; Natural seawater splitting; Urea electrolysis
• ISSN: 2095-4956
• DOI: 10.1016/j.jechem.2024.07.010

The interface boundaries between Ni2P-MoO2 play an essential role in modulating a coordination number of intermediates to break the energy scaling relation, which exhibits eminently catalytic activity for urea-assisted natural seawater electrolyzer. [Display omitted] Urea-assisted natural seawater electrolysis is an emerging technology that is effective for grid-scale carbon–neutral hydrogen mass production yet challenging. Circumventing scaling relations is an effective strategy to break through the bottleneck of natural seawater splitting. Herein, by DFT calculation, we demonstrated that the interface boundaries between Ni2P and MoO2 play an essential role in the self-relaxation of the Ni–O interfacial bond, effectively modulating a coordination number of intermediates to control independently their adsorption-free energy, thus circumventing the adsorption-energy scaling relation. Following this conceptual model, a well-defined 3D F-doped Ni2P-MoO2 heterostructure microrod array was rationally designed via an interfacial engineering strategy toward urea-assisted natural seawater electrolysis. As a result, the F-Ni2P-MoO2 exhibits eminently active and durable bifunctional catalysts for both HER and OER in acid, alkaline, and alkaline seawater-based electrolytes. By in-situ analysis, we found that a thin amorphous layer of NiOOH, which is evolved from the Ni2P during anodic reaction, is real catalytic active sites for the OER and UOR processes. Remarkable, such electrode-assembled urea-assisted natural seawater electrolyzer requires low voltages of 1.29 and 1.75 V to drive 10 and 600 mA cm−2 and demonstrates superior durability by operating continuously for 100 h at 100 mA cm−2, beyond commercial Pt/C ‖ RuO2 and most previous reports.