Efficient Transition Metal Sulfide Electrocatalysts Prepared by Laser-Induced Precursor Decomposition

Transition metal sulfides (TMSs) are renowned for their outstanding catalytic performance, earth abundance, and low cost and are widely used as electrocatalysts for flexible energy devices. However, their common synthesis processes usually involve harsh conditions, such as high temperature, high vacuum, and time consumption due to the high formation energy of TMSs, which make it difficult to prepare TMSs on temperature-sensitive plastic substrates. In this work, we synthesized TMS catalysts with superior catalytic activity by a fast, simple, and low-temperature laser-induced precursor decomposition (LIPD) method. A series of metal-organic complexes (M[BDCA](x)), composed of the sulfur-rich decomposable butyldithiocarbamic acid (BDCA) ligands, were chosen as the precursors, which tend to decompose under the irradiation of a nanosecond-pulsed Nd:YAG laser (355 nm). It was found that precursors with a high molar extinction coefficient, such as Co[BDCA](x) and Ni[BDCA](x), were decomposed rapidly and completely under this laser to form CoSx and NiSx, respectively. The as-prepared CoSx and NiSx showed excellent electrocatalytic properties toward triiodide reduction, comparable with the pyrolyzed Pt. Using LIPD-prepared CoSx and NiSx films as counter electrodes, we fabricated dye-sensitized solar cells with a power conversion efficiency of similar to 8.5%. This LIPD method ensures the formation of TMSs near room temperature (<30 degrees C), which is feasible to prepare TMS films on the temperature-sensitive plastic substrates, facilitating their applications in portable electrochemical energy devices.