Controlling Chlorine-Doped Nickel Diselenide Ultrathin Nanosheets through Steric Effects: An Electrocatalyst for Oxygen Evolution Reaction and Urea Oxidation Reaction

Exploration of electrocatalysts suitable for the oxygen evolution reaction (OER) and urea oxidation reaction (UOR) is essential for electrocatalytic hydrogen production. In this work, a ligand substitution strategy is used to synthesize ultrathin-nanosheet electrocatalysts of Cl-doped NiSe₂ (NiSe₂-a and NiSe₂-b), which exhibit high-electrocatalytic activity during OER and UOR. NiSe₂-a and NiSe₂-b only need an overpotential of 227 and 268 mV, respectively, to achieve a current density of 10 mA cm^-2 during OER. Furthermore, NiSe₂-a with its smaller steric effects exhibits excellent catalytic performance for UOR, requiring an ultralow potential of 1.360 V to deliver a current density of 100 mA cm^-2. This excellent performance can be attributed to the nonmetallic elements (Se and Cl) modulating and optimizing the charge state of the metal sites, thereby increasing the electrocatalytic activity. Overall, this work provides an unparalleled example of tuning space structures to design efficient electrocatalysts and has promising industrial applications.