Fig. 1: Diagram of a QWCS.
a, The structure of a quantum well transistor. In a quantum well transistor, the on/off state between the source and drain depends on the voltage applied to the gate, which changes the electronic conductivity of the electronic channel. b, Diagram of the quantum well catalytic structure for Ni@C-MoOx in the QWCS. The on/off state between the catalytic centre (Ni or Ni-C-MoOx) and current collector (MoOx or carbon) depends on the adsorption of reactants, which changes the electron conductivity of C-MoOx (acting as an electron channel). c, Schematic diagram of the band structures and the corresponding electron transfer process for the QWCS and traditional Ni catalyst, where VB is the valence band and CB is conduction band. Electrons of the Ni nanoparticles are confined by the barrier of QWCS, and Ni electrooxidation was forbidden (off state); whereas the QWCS gained electrons from the adsorption of donor-doped hydrogen, increasing the Fermi level and the electronic conductivity for the HOR reaction.
