Fabrication of Co- and P-Doped Laser-Induced Graphene for Use in Water Splitting Applications

The efficient production of high-purity hydrogen for green energy using water splitting requires cost-effective and high-performance electrodes for the hydrogen evolution reaction (HER). Conventional catalyst coating methods, such as chemical vapor deposition and electrochemical deposition, are often complex and expensive; thus, there is a need to develop more efficient alternatives. In this respect, cost-effective nickel-foam-based catalytic electrodes have demonstrated promising HER activity, while laser-induced graphene (LIG) offers desirable characteristics such as high microporosity, excellent conductivity, chemical stability, a 3D structure, and scalability. This study focuses on utilizing LIG as a catalyst support for the deposition of catalytic materials on nickel foam for the HER. Our proposed fabrication technique involves drop-coating cobalt and phosphorus in a poly(amic acid) solution onto nickel foam, followed by annealing to form a doped polyimide polymer. Subsequent CO 2 laser irradiation converts the polymer into conductive LIG doped with cobalt oxide and phosphorus (CoP-LIG). The CoP-LIG on nickel foam (CoP-LIG-Ni) exhibits significantly enhanced HER activity compared to pristine nickel foam and undoped LIG-Ni (u-LIG-Ni), with an onset potential as low as 0.127 V and a Tafel slope of 64 mV/dec. The coating exhibits excellent durability and desirable bubble evolution. Overall, the proposed CoP-LIG-Ni fabrication process is simple, cost-effective, and scalable, thus advancing nickel-foam-based water electrolysis and material-incorporation technologies.