Operando Synthesis of a Dendritic and Well-Crystallized Molybdenum Oxide/Silver Catalyst for Enhanced Activity in the Hydrogen Evolution Reaction.

Dendritic MoO3/Ag with good crystallinity has been prepared through an operando method. In the hydrogen evolution reaction (HER), this catalyst, which was designed to utilize the best properties of each component material, showed a high catalytic activity. After the precursor was drop-cast onto a glassy carbon electrode, a reductive potential was applied to the coated electrode, and H2 evolution occurred within the range of potentials. The overpotential required to evolve H2 at the benchmark rate decreased progressively with subsequent voltammetric cycles, until a steady state was reached at which only 145 mV of overpotential was required to pass −10 mA cm−2 of current density. During the electrocatalysis, the precursor was converted to catalyst through an operando method. This operando-synthesized MoO3/Ag catalyst has a low Tafel slope (43 mV dec−1), low overpotential (145 mV), and excellent durability for HER. It has the potential to be a promising material for HER. [ABSTRACT FROM AUTHOR]