Ultrasonic treatment-assisted reductive deposition of Cu and Pd nanoparticles on ultrathin 2D BiS nanosheets for selective electrochemical reduction of CO into C compounds.

In this work, we have ultrasonically deposited Cu and Pd nanoparticles on BiS nanoparticles, prepared using an ultrasonication assisted hydrothermal method. We implemented intense ultrasonic waves bearing frequency of 20 kHz and power of 750 W at the acoustic wavelength of 100 mm to reduce Cu and Pd nanoparticles on the BiS surface. The XRD confirmed the formation of highly crystalline BiS nanoparticles with a pure orthorhombic phase and the deposition of copper (Cu) and palladium (Pd) nanoparticles was indicated by the strengthening and broadening of the peaks. XPS also confirmed the formation of Cu and Pd nanoparticles on BiS. The Transmission Electron Microscopy (TEM) also exhibited the deposition of Cu and Pd nanoparticles on the BiS nanosheets which was further confirmed using high resolution TEM analysis. The electrochemical CO reduction by Cu-Pd/BiS electrocatalyst using Cu foam as the conducting support led to the formation of acetaldehyde and ethylene as the major products. The rate of formation of ethylene was found to be 488.5 μ mol gh at an applied potential of -0.6 V (vs. RHE), with the best Faradaic efficiency of 57.09 % at -0.4 V (vs. RHE). Among the liquid phase products, acetaldehyde was the major product showing the maximum Faradaic efficiency of 6.473 % at -0.2 V (vs. RHE), with a total formation rate of 64.27 μ mol gh. The results revealed that the Cu-Pd/BiS electrocatalyst was more selective to C products while the pure BiS nanoparticles majorly produced C compounds.