Visible light-active binary metal ion containing functional triazine metallopolymers as a stable p-type photo-electrocatalyst in protic electrolytes

Visible light-active metallo-organic coordination systems have versatile opportunities due to their tunable electronic properties. Herein, we report a photocathode based on triazine trithiolate network polymers containing mixed metal ions of Cd²⁺ and Cu^2+/1+ with enhanced photoelectrochemical activity in acidic electrolytes. These thin films were prepared by the facile and direct chemical immobilization of cadmium ion containing triazine trithiolate units on a copper substrate through Cu-S linkage. The copper ions generated through controlled anodization enable the facile growth of mixed metal ion containing triazine trithiolate metallopolymers. The XPS analysis confirms the presence of Cd²⁺ and Cu^1+/2+ in the metallopolymeric thin films. Photoelectrochemical investigations suggest the p-type behavior with repeatable photocurrent of nearly 40-60 μA cm⁻² at higher reductive potentials (−0.6 V vs. Ag/AgCl) in 0.5 M H₂SO₄. Furthermore, these electrodes show −148 mV vs. RHE to attain 10 mA cm⁻² for hydrogen evolution in 0.5