Insights into the synergistic promotion of spin polarization over C₃N_5.4 for enhancing cooperative hydrogen evolution and benzylamine oxidation coupling

Polymers are usually restricted on the high exciton binding energies and sluggish electron transfer because of the low dielectric constants. Regulating spin-polarized electrons is regarded as an attractive strategy, but often confined to the d-orbital elements. Here, the nonmetal P and N elements co-mediated the spin polarization of carbon nitrides (PCN) have been elaborately designed. The optimized PCN-3 shows an outstanding hydrogen production (22.2 mmol·g^–1·h^–1) coupled with selective benzylamine oxidation without using any solvent and cocatalysts, which is 200 times of original C₃N₄ and superior to the photocatalysts has been reported to date. Experimental and theoretical results verified that the spin-orbital coupling of N 2p and P 2p remarkably increased the parallel spin states of charge and reduced the formation of singlet excitons to accelerate exciton dissociation in carbon nitride. In addition, charge separation and surface catalysis can be significantly enhanced by the electron spin polarization of carbon nitride with the parallel arrangement, huge built-in electric field and disturbed electronic structure. Our finding deepens the insight into the charge separation and exciton dissociation in spin polarization, and offers new tactics to develop high-efficiency catalysts.