Cobalt decorated ultra-thin Ti3C2 MXene electrocatalyst for high-efficiency hydrogen evolution reaction

The spindle ultra-thin Ti3C2 MXene nanotablets are successfully fabricated by high energy ultrasonic wave treatment. The as-prepared Ti3C2 are terminated with =O, −OH or/and −F groups. The Co nanoparticles are bonded with Ti3C2 nanotablets and form Ti3C2(O2-xH2-x-2mFxCom) hybrid by refluxing approach. Zeta potential measurement illustrates that the Co nanoparticles carry positive charge while the Ti3C2 nanotablets carry negative charge, implying that there is a transfer path of electron density from Co nanoparticles to Ti3C2 nanotablets. As a result, the Co acts as the hydride-acceptor and Ti3C2 acts as the proton-acceptor in Co-Ti3C2 hybrid. Compared with Co nanoparticles and Ti3C2 nanotablets, the Co-Ti3C2 hybrid exhibites low overpotential, low Tafel plot and high electrocatalytic property. The introduction of Co nanoparticles can effectively enhance the conductivity of bulk Ti3C2 and accelerate the charge transfer rate between Co and Ti3C2, which are beneficial for the electrocatalytic performance.