Oxygen activation of noble-metal-free g-C3N4/α-Ni(OH)2 to control the toxic byproduct of photocatalytic nitric oxide removal

Photocatalytic NO x removal is regarded as a promising technique for air purification in recent years. However, NO x removal process usually accompanies with toxic NO 2 generation, leading to serious secondary pollutant and limiting its practical application. Herein, a noble-metal-free g-C 3 N 4 /α-Ni(OH) 2 photocatalyst was fabricated through hydrothermal method. The introduction of α-Ni(OH) 2 microspheres combines with g-C 3 N 4 , resulting in an enlarged surface area from 35 to 95 m 2 /g, while the unique structure of α-Ni(OH) 2 broadens visible-light response range and accelerates photogenerated charge carriers transfer. More importantly, the H atoms of α-Ni(OH) 2 improve the adsorption and activation of O 2 and oxygen atoms to promote NO and NO 2 oxidized to nitrate. Consequently, g-C 3 N 4 /α-Ni(OH) 2 shows enhanced NO removal ratio of 51.3% without any toxic NO 2 generation, indicating its great potential for air purification. Our results provide fresh insight into the design of highly efficient and safe photocatalyst for toxic byproduct control in the application of environmental remediation.