Photocatalytic Reduction of CO 2 to C 2 H 4 on Palladium–Iron-Loading Phosphorus via Promoting C–C Linking and Suppressing CO Generation

Photocatalytic reduction of carbon dioxide is a clean and sustainable method for carbon emission reduction. However, most of the reported photocatalysts for CO 2 reduction can produce only CO and CH 4 . Phosphorus with the bandgap of 1.6 eV is a promising photocatalyst, but the slow C–C coupling efficiency renders pure phosphorus to fail to produce C2 products. Herein, we found that the iron-modified Red P photocatalyst can reduce CO 2 to C 2 H 4 and C 2 H 6 . The yield of C 2 H 4 (32.47 μmol·g –1 ·h –1 ) is much higher than that of CO (2.04 μmol·g –1 ·h –1 ), CH 4 (2.36 μmol·g –1 ·h –1 ). Moreover, when PdFe substitutes for Fe, no C 2 H 6 is produced, the generation of C 2 H 4 further increases, while CO and CH 4 are suppressed, with their yields decreasing by about 72.8 and 17.5 times, respectively. The yield of C 2 H 4 increases to 44.91 μmol·g –1 ·h –1, and its selectivity of C 2 H 4 increases to 99.79%, which is the highest value among state-of-the-art photocatalysts. The C–C coupling can be achieved through a “channel” between Fe atoms in the Fe–P system. This study proposes a catalyst for reducing carbon dioxide to ethylene and broadens people’s understanding and application of photocatalysts.