Single-step synthesis of silicon carbide anchored graphitic carbon nitride nanocomposite photo-catalyst for efficient photoelectrochemical water splitting under visible-light irradiation

Abstract

Visible-light active, silicon carbide (SiC) anchored graphitic carbon nitride (g-CN) nanocomposites (g-CN-SiC), with different SiC concentrations were synthesized using pulsed laser ablation in liquid (PLAL). Initially g-CN was synthesized by simple thermal pyrolysis, and subsequently SiC was loaded on the g-CN polymer network by PLAL to obtain g-CN-SiC polymeric-inorganic nanocomposites. The proper formation of g-CN-SiC nanocomposites is proven by XRD, SEM, TEM, and the elemental composition and the variation of elemental peaks in the nanocomposite due to the change of chemical environment was studied by XPS analysis. The synthesized g-CN-SiC were tested for their applicability as a catalyst in the process of photo-electrochemical water splitting for hydrogen production, a simple step ahead towards the realization of energy efficient fuel cells. The hydrogen production was quantified by measuring photocurrent density in the linear sweep voltammetry, and it was found that when g-CN-SiC is used in the photoanode, the measured photocurrent is consistently more than that produced by g-CN photoanode, with the highest observed photocurrent density for g-CN-SiC with 10 % SiC content, accounting for a seven-fold increase of photocurrent compared to pure g-CN. Enhanced visible light absorbance, and reduced photo-generated charge recombination in g-CN-SiC, observed in the absorption and photoluminescence spectra respectively can be attributed to the improved photo electrochemical activity of g-CN-SiC based photoanode in the process of water splitting.