Robust P-N Heterojunction Polymer Nanocomposites: Advanced pH-Universal Electrocatalysts for Highly Efficient and Stable Water-Splitting Hydrogen Production

Abstract

The development of hydrogen energy is key in order to move toward net-zero carbon emissions; however, efficient, low-cost, pH-universal hydrogen evolution reaction (HER) catalysts remain a significant challenge. Organic polyaniline (PANI) and inorganic exfoliated molybdenum diselenide (MoSe2) nanosheets are P-type and N-type semiconductors. Their combination facilitates formation of an organic-inorganic P-N heterojunction interface, which promotes efficient charge transfer from PANI to MoSe2 and enhances HER catalysis under universal pH conditions. Here, we successfully constructed a MoSe2/PANI composite catalyst with a P-N heterojunction interface and excellent electrocatalytic performance by integrating biopolymer-functionalized exfoliated MoSe2 nanosheets with PANI on conductive nickel foam (NF) substrate through electropolymerization and electroactivation. Compared to the commercial platinum-carbon catalyst, MoSe2/PANI/NF exhibits superior electrocatalytic HER performance in acidic, alkaline, and simulated seawater electrolyte solutions, with similar Tafel slopes and lower overpotential and resistance values. Importantly, after 24 h of operation (100 mA/cm2) or 1000 cycles of cyclic voltammetry scanning in acidic and simulated seawater conditions, MoSe2/PANI/NF demonstrated excellent catalytic stability and environmental tolerance, indicating potential to achieve efficient and highly stable water electrolysis for hydrogen production. Therefore, this emerging system may enable the development of pH-universal, non-precious metal electrocatalysts for various energy applications.