The In-situ Growth NiFe-layered Double Hydroxides/g-C 3 N 4 Nanocomposite 2D/2D Heterojunction for Enhanced Photocatalytic CO 2 Reduction Performance

A tightly 2D/2D heterojunction of g-C3N4(g-CN)/NiFe-layered double hydroxides (NiFe-LDH) was prepared in situ. The proper band-gap matching between NiFe-LDH and g-CN increased the transfer pathway of photogenerated electrons and holes between semiconductors. This in turn effectively reduced the recombination rate of photogenerated electrons and holes. Meanwhile, addition of g-CN to the matrix modified the surface morphology of NiFe-LDH and prevented agglomeration of two-dimensional materials while increased their ductility. Moreover, specific area of NiFe-LDH was found 3.06 times larger for 5:1-NiFe-LDH/0.8 g-CN as compared to 5:1-NiFe-LDH. The larger surface area results in availability of multiple reaction sites for the reduction of CO2. Upon exposure to light for 4 h, the product revealed 55.79 μmol/g and 20.45 μmol/g efficiency for CO and CH4 respectively, which was 3.57 times higher than pure NiFe-LDH and 4.25 times higher than pure g-CN. Furthermore, the product revealed as high as 73.2% selectivity for CO. Results authenticate the prepared g-CN containing NiFe-LDH as highly stable, efficient and selective two-dimensional materials for CO2 reduction upon exposure to light.