Binary electrocatalyst composed of Mo2C nanocrystals with ultra-low Pt loadings anchored in TiO2 nanotube arrays for hydrogen evolution reaction

Abstract Pt is the most effective electrocatalyst for hydrogen evolution reaction (HER). But its practical applications are severely hindered by the high cost and low abundance. Herein, we proposed a facile strategy to significantly reduce the Pt loadings for HER application. By introducing a Pt counter electrode in electrochemical cycling, trace Pt species were dissolved and redeposited on the working electrode composed of Mo2C nanoparticles anchored on the inner wall of highly ordered TiO2 nanotube arrays (TiO2 NTAs). Highly-dispersed Pt species were embedded in the crystal defects of Mo2C nanostructures with high dispersion and ultra-low Pt loading of ~13 μg/cm2. The as-prepared Pt-Mo2C/TiO2 NTAs exhibit highly electrocatalytic activities towards HER with an overpotential of 67 mV at the current density of 10 mA cm−2. Excellent stability has also been demonstrated. The mass activity of Pt-Mo2C/TiO2 NTAs is about 8-folds greater than that of commercial Pt/C electrode.