Mass synthesis of Pt/C catalysts with high Pt loading for low-overpotential hydrogen evolution

Abstract

We present a facile and scalable method to synthesize Pt/C catalysts with high Pt loading (10–30 wt.%) using sodium polyacrylate resin (PAANa) as a multifunctional agent. PAANa can absorb H2PtCl6 solution and form a gel, which can be converted into Pt/C catalysts by pyrolysis. PAANa acts as a water absorber, a Pt stabilizer, and a carbon precursor. The optimized catalyst, pyrolyzed at 800 °C with a 20 wt.% Pt loading, demonstrates Pt nanoparticles measuring 3.5 nm in size. It exhibits excellent stability and achieves a low overpotential of 43 mV at a current density of 10 mA cm−2 for the hydrogen evolution in alkaline media. The enhanced catalytic activity is due to the combined influence of the nanoscale Pt particles, the higher degree of graphitization, and the porous carbon substrate with a large surface area. We also demonstrate the scalability of the method by producing 100 g of the catalyst in the laboratory.