Transition Metal-Doped MoS₂ Ultrathin Film for CO₂ Photoreduction

Photocatalytic CO₂ reduction is a promising approach which can not only attenuate this greenhouse gas but also generate solar fuels, simultaneously. However, there is still significant challenges, i.e., low efficiency and selectivity, hindering the studied photocatalyst to be applied for industrial-scale applications. It seems introducing the catalytic active sites and shedding light on the reaction pathways would address the above-mentioned issues. In this regard, we propose introducing transition metal dopants into the crystal structure of inert MoS₂ to modify its basal plane for CO₂ activation. Beyond active site modulation, dopants can further change the electronic structure resulting in a tunable semiconducting type, tunable opto-electrical response, stabilizing the favored intermediates, and forming dopant–vacancy pairing. Wafer-scale MoS₂ ultrathin films, ~3 nm confirmed by atomic force microscopy, are synthesized by one step and facile solution-based thermal decomposition method. This method, by adding the dopant precursor, can assist to directly introduce dopant into the MoS₂ crystal structure without further post treatments. Raman scattering spectroscopy is widely used to investigate the lattice vibrational modes of the pristine and doped MoS₂. The TEM image provides direct evidence of Ni substitution at the Mo site. Moreover, the photocatalytic performance of doped MoS₂ demonstrates significant enhancement compared to pristine MoS₂. According to the results, by fine tuning the growth parameters, this work demonstrated that the solution based thermal decompaction is a promising way to fabricate doped large-scale transition metal chalcogenides ultrathin films. This method shows potential applications in catalysis and other related fields.