Ag–NiP deposited green carbon channel embedded NiP panels for sustainable water splitting†

Abstract

Ag–NiP-deposited carbon channels on NiP panels were successfully developed through lemon juice extract (Ag–CL/NiP) and citric acid (Ag–CC/NiP)-assisted methodologies. The methods involved the precise execution of electroless deposition of the advanced Ag–carbon matrix with NiP. The lemon juice-assisted method produced carbon channels with a dense concentration of Ag–NiP on the electrode surface, whereas the citric acid method resulted in a less dense deposition of Ag–NiP on the electrode surface, as observed via FE-SEM. The Ag–CL/NiP has remarkably higher electro- and photocatalytic water splitting performance due to the compact and conductive Ag–NiP connected with carbon channels. Electrochemical impedance analysis of Ag–CL/NiP revealed a low R_ct of 491.3 Ω at the open circuit potential, indicating enhanced conductivity. The electrocatalytic oxygen evolution reaction (OER) overpotential of Ag–CL/NiP was 401 mV to achieve a current density of 50 mA cm⁻², with a Tafel slope of 46.5 mV dec⁻¹. The panel exhibited good stability, with a proven durability of over 1000 cycles of CV during OER. The developed panel achieved an impressive photocurrent density of ∼9.5 mA cm⁻² at 1.37 V vs. RHE when subjected to light irradiation with a wavelength exceeding 420 nm. Furthermore, the Ag–CL/NiP panel demonstrated the ability to generate 17.5 mmol cm⁻² of H₂ over a 4-hour sunlight irradiation period. The temperature-controlled photocatalytic water splitting experiment revealed that the panel maintained its activity at temperatures as low as ∼12 °C, but with a 40% drop in efficiency compared to normal sunlight conditions.