Cross-linked ultrathin polyphosphazene-based nanosheet with promoted charge separation kinetics for efficient visible light photocatalytic CO2 reforming to CH4

Organic polymer materials as a promising type of photocatalyst are still limited by the poor transport efficiency of photoinduced carrier. Herein, a series of cross-linked ultrathin polyphosphazene-based nanosheets is developed by regulating the N-containing skeleton. The aromatic ring, pyrimidine ring and s-triazine ring are bonded with cyclotriphosphazene to form large-sized 2D nanosheets, respectively. Experimental results and theoretical calculations have determined the pyrimidine ring that has a stronger ability to adsorb CO2 and can provide a suitable band gap and a stronger built-in electric field, so as to realize the rapid separation of photoproduced carrier. 2PC sample with the pyrimidine ring delivered near 100% selectivity for CO2-to-CH4 conversion with an impressive rate of 626 µmol g−1 without cocatalyst and photosensitizer under visible light illumination, surpassing many reported photocatalysts. Briefly, this work offers a fresh means for the construction of high-performance polymers by regulating the internal framework.