Ultrasonic-assisted solution mixing method for preparing NiPPc/MoS₂ composite material for electrocatalytic reduction of CO₂ to produce syngas

The inexpensive, high-activity, and highly efficient electrocatalysts are the critical materials to reduce the concentration of CO₂ and fully utilize its reduction products. In the present paper, the catalyst of nickel polyphthalocyanine (NiPPc)/MoS₂ is prepared by the ultrasonic-assisted solution mixing method. The conductive carrier of MoS₂ will provide an attachment plane for NiPPc and enhance the conductivity of the whole catalyst, the catalytic performance of the NiPPc/MoS₂ is thus optimized. The current density of the catalyst obviously increases after loaded. There is a current density of 25 mA∙cm⁻² for mass fraction 7% NiPPc/MoS₂ at −1.0 V compared with the reversible hydrogen electrode (RHE). For mass fraction 9% NiPPc/MoS₂ at −1.1 V (vs. RHE), the current density is 43.20 mA∙cm⁻². Required potential of mass fraction 7% NiPPc/MoS₂ is less that MoS₂ and NiPPc, and the capacitance of double layer (C_dl) value is higher than that of MoS₂ (0.639878 mF∙cm⁻²) and NiPPc (0.809429 mF∙cm⁻²). In addition, the CO partial current densities of mass fraction 7% NiPPc/MoS₂ at −1.0 V and −1.1 V (vs. RHE) are 22.07 mA∙cm⁻² and 22.81 mA∙cm⁻², Faraday efficiency of CO (FE_CO) will be 86% and 58% respectively. Meanwhile, mass fraction 7% NiPPc/MoS₂ exhibit the excellent performance in syngas production at high potentials.