Sulfur-Modified Nickel-Based Hybrid Nanosheet as a Robust Bifunctional Electrode for Hydrogen Generation via Formaldehyde Reforming
Weixia Huang, Yiming Guo, Xujiang Cen, Yun Tong, Lu Chen, Pengzuo Chen
Abstract
Coupling the electrochemical oxidative upgrading of formaldehyde (FOR) with hydrogen evolution reaction (HER) toward energy-efficient H 2 production and simultaneous chemical production is important, but it still faces huge challenges. Herein, a unique hierarchical heterojunction is designed by coupling a Ni(OH) 2 nanosheet with S-modified Ni species on a nickel foam substrate (S–Ni@Ni(OH) 2 /NF) via a two-step strategy. The Ni(OH) 2 nanosheets with a large surface area contribute to offering sufficient sites for the grafting of S–Ni species, constructing a coupled heterostructure to realize greatly improved reaction kinetics for both HER and FOR processes. As a result, S–Ni@Ni(OH) 2 /NF delivers an overpotential of 50 mV for HER at 10 mA cm –2 and a low potential of 1.36 V to acquire a current density of 50 mA cm –2 for FOR. For the HER||FOR-coupled system, the built-in electrolyzer only needs 1.58 V to realize 50 mA cm –2 as well as superior stability. This work presents a facile strategy to exploit bifunctional electrodes for hydrogen generation via an energy-saving way with coupled formaldehyde reforming.