MOF-derived tunable spin-state MnIII doped g-C3N4 photocatalysts with enhanced photocatalytic activity

In this study, we designed and synthesized Mn-III with tunable spin state in g-C3N4 through one-step calcination of Mn-MOF. The Mn atoms were induced into the six-fold cavity of the g-C3N4 lattice and formed Mn-N-6 coordination. Mn-MOF served as the source of Mn. The collapse of Mn-MOF effectively promoted the stripping of stacked layers in g-C3N4 and increased the atomic loading. The Mn-N coordination induced impurity energy levels which effectively regulated Mnx-CN's bandgap structure and accelerated the migration and separation of carriers. The (center dot)O(2)(-)was activated to O-1(2) by the energy released from the high-spin Mn-III transferred ground state. The H-2 production of Mn-10-CN (13479.19 mu mol.g(-1).h(-1)) is similar to 32.2 times that of CN under visible light irradiation and with a remarkable apparent quantum yield (AQY) of 12.23% at 420 nm. The rates of TC degradation and Cr (VI) reduction achieved 0.059 and 0.18 min(-1), respectively. In addition, the practical application conditions and catalytic mechanism of Mnx-CN were explored. This work demonstrates the connection of the spin state of metal with the photocatalytic activity, providing an efficient photocatalytic system that can be used for solar-chemical energy conversion and pollution remediation, and presenting a new approach for modifying the g-C3N4-based catalysts.