Nitrogen and sulfur-enriched 3D-Triptycene based microporous polymer as efficient electrocatalyst for alkaline hydrogen evolution reaction

The development of electrocatalysts for efficient and sustainable hydrogen production is crucial for renewable energy conversion and storage. Herein, we report the synthesis and evaluation of a 3D triptycene and phenothiazine-based microporous polymer (NS-TMP) as an electrocatalyst for the alkaline hydrogen evolution reaction. The NS-TMP exhibited strong HER activity in a 1.0 M KOH solution, with a Tafel slope of 48 mV dec⁻¹. To enhance catalytic performance, we employed laser-assisted annealing to produce N, S-codoped carbon (LA–NS–TMPC), improving the electrocatalyst's structural and compositional properties. The LA–NS–TMPC showed superior activity, with a Tafel slope of 48 mV dec⁻¹, close to commercial Pt/C (42 mV dec⁻¹) and significantly lower than bare nickel foam (156 mV dec⁻¹), indicating a Volmer−Heyrovsky reaction pathway. The LA–NS–TMPC electrode demonstrated remarkable HER performance, requiring overpotentials of only 80 mV and 220 mV to achieve current densities of 10 mA cm⁻² and 100 mA cm⁻², respectively. Additionally, the electrocatalyst exhibited excellent stability over 48 h, emphasizing its potential in water electrolyzers, fuel cells, and other renewable energy technologies.