Electrochemical investigation of Pd-Au/BC nanocomposite-biochar and their photocatalytic and energy storage applications

Abstract

This study introduces a new method for producing a Pd-Au/BC nanocomposite, suitable for photocatalysis and photoelectrode applications, with enhanced visible light activity. Characterization of the nanocomposite was conducted using UV/Vis spectroscopy, FTIR, XRD, SEM, XPS, and BET analyses. Cyclic voltammetry revealed a specific capacitance of 690F g−1, 290F g−1, 190F g−1, and 150F g−1 at current densities ranging from 0.2 mV to 0.5 mV. The reduction and oxidation peaks were observed during cyclic voltammetry, indicating the electrochemical behavior of the nanocomposite. In the initial scan, a noticeable reduction peak was observed around 0.13 V. In cycles 2 to 3, two anodic peaks emerged around 0.20 and 0.29 V. Photocatalytic experiments demonstrated the nanocomposite's efficacy in degrading Congo red under visible light irradiation. The uniform contour of the curve is notable, signifying the continued functionality of the supercapacitors up to a voltage threshold of 0.72 V. When the effective voltage window is expanded from 0.00 V to 0.46 V at a current density of 0.46 A g−1, it results in nonlinear symmetric charge and discharge profiles. The electrochemical process generated hydroxyl radicals (OH), aiding in pollutant breakdown. Anodic peaks appeared at potentials of 0.18 V, 0.52 V, and 0.86 V, indicating the electrocatalytic activity of the nanocomposite. This enhancement is attributed to the suppression of electron-hole recombination, extending the nanocomposite's responsiveness to visible light. Overall, the synthesized Pd-Au/BC nanocomposite exhibits promising applications in both photocatalysis and electrochemical processes.