Three-Dimensional Network of Highly Uniform Cobalt Oxide Microspheres/MXene Composite as a High-Performance Electrocatalyst in Hydrogen Evolution Reaction.

Due to its affordable cost, excellent redox capability, and relatively effective resistance to corrosion in alkaline environments, spinel Co 3 O 4 demonstrates potential as a viable alternative to noble-metal-based electrocatalysts. Nevertheless, these materials continue to exhibit drawbacks, such as limited active surface area and inadequate intrinsic conductivity. Researchers have been trying to increase the electrical conductivity of Co 3 O 4 nanostructures by integrating them with various conductive substrates due to the low conductivity of pristine Co 3 O 4 . In this study, uniform cobalt glycerate solid spheres are first synthesized as the precursor and subsequently transformed into cobalt oxide microspheres by a simple annealing procedure. Co 3 O 4 grown on the surface of Ti 3 C 2 T x -MXene nanosheets (Co 3 O 4 /MXene) was successfully synthesized through electrostatic attraction. In order to create a positively charged surface, the Co 3 O 4 microspheres were treated with aminopropyltriethoxysilane. The Co 3 O 4 /MXene exhibited a low overpotential of 118 mV at 10 mA cm -2 and a Tafel slope of 113 mV dec -1 for the hydrogen evolution reaction, which is much lower than the pristine Co 3 O 4 at 232 and 195.3 mV dec -1 .