The improved water oxidation at neutral pH using field bindweed and NiCo- layered double hydroxides

High-efficiency and environmental electro-catalyst are prepared for the water oxidation. Here, we report nitrogen doping-carbon quantum dot (N-CQD) that is prepared from field bindweed using the hydrothermal method. Also, NiCo-layered double hydroxide (LDH) was prepared using a simple method. The prepared samples were characterized using several techniques that confirmed the successful preparation of N-CQD and NiCo-LDH. Also, the effect of molar ratios of Ni: Co on the morphology of NiCo-LDH were studied by the Field Emission-Scanning Electron Microscopy (FE-SEM). The obtained images obviously reveal that apply several molar ratios of Ni and Co can affect the morphology and optimized molar ratio Ni: Co was 1: 1. Then, we use N-CQDs combination with the optimized NiCo-LDH for water oxidation. The resulting NiCo-LDH/N-CQD shows improved electro-catalytic activity in comparison with pure NiCo-LDH (with an onset-potential of 1.55 V (vs. RHE) and overpotential about similar to 325 mV in neutral media) for oxygen evolution. The enhanced water oxidation activity is attributed to the association of the NiCo-LDH with N-CQDs. N-CQDs which supply rapid electron transfer, supreme conductivity, and electron reservoir characters that are caused to the rapid electron transfers from N-CQDs to NiCo-LDH on the surface and consequently, could further increase the electro-catalytic reaction.

Automated summary

High-efficiency and environmental electro-catalysts for water oxidation were prepared, including nitrogen doping-carbon quantum dots (N-CQD) and NiCo-layered double hydroxide (LDH). The morphologies of NiCo-LDH were influenced by the Ni:Co molar ratios, with the optimized ratio being 1:1. Combining N-CQDs with NiCo-LDH improved electro-catalytic activity for water oxidation, attributed to the rapid electron transfer capabilities of N-CQDs.