High-performance HER on magnetron-sputtered nanometric Nb films on porous silicon substrates.

The hydrogen evolution reaction (HER) stands out as one of the most extensively studied electrocatalytic reactions in literature. Herein, niobium has been tested for the first time for the catalysis of the HER in the form of nanometer-thick-films. The deposition of 5, 10, and 50 nm-thick Nb thin films onto both smooth and porous silicon substrates, the latter ones with mesopores with mean diameters of 13 nm and 7 nm, respectively, has been successfully achieved using magnetron sputtering, a highly precise and controllable technique allowing a very efficient deposition of Nb films. After the sputtering deposition, the samples were examined by Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Analysis (EDAX) analyses which confirmed the purity and uniformity of the Nb coating on all samples. Electrochemical tests revealed top-notch performance, with almost negligible onset potentials (es. 80 mV vs. RHE) and low Tafel slopes (es. 30 mV/dec), thereby paving the way for the future development of cutting-edge devices. • Niobium tested for the first time towards HER in the form of nanometer-thick-films. • Deposition of 5, 10, and 50 nm-thick Nb films on smooth and porous Si substrates. • Highly precise efficient and controllable deposition through magnetron sputtering. • Negligible overpotentials and low Tafel slopes. • Paving the way for H 2 production in a single, integrated Si-based device. [ABSTRACT FROM AUTHOR]