A readily synthesis of oxygen vacancy-induced In(OH)3/carbon nitride 0D/2D heterojunction for enhanced visible-light-driven nitrogen fixation

Abstract A promising and practicable catalyst is the key challenge for industrial perspective to promote photocatalytic nitrogen fixation. In this study, a new 0D /2D heterojunction, oxygen vacancy-induced In(OH)3 /carbon nitride (OV-In(OH)3/CN), was synthesized by generating In(OH)3 nanoparticles on g-C3N4 nanosheets in the presence of glyoxal through a facile and readily precipitation growth method at 60℃and under atmospheric pressure. The existence of oxygen vacancies, structure, morphology and optical-electronic properties of the composite were characterized by HRTEM, XPS and EPR analysis and other measurements. The OV-In(OH)3 /CN heterojunction exhibited excellent photocatalytic activity for nitrogen fixation with a good chemical stability. The OV-In/CN-3 sample reached the maximum NH3 generation rate to be 3.81 mM*h−1*g−1, which was about 10 times as that of pure g-C3N4 and was also higher than that of other catalysts reported. Though the In(OH)3 in heterojunction was demonstrated incapable of producing photogenerated electrons under vis-light irradiation, its oxygen vacancy was found to “receive” and “trap” some excited electrons from g-C3N4, promoting electron-hole pairs separation efficiency and prolonging the lifetime of carriers. And it also can introduce many chemisorption sites for N2. Those are the two key reasons for its high photocatalytic activity.