Rational Design of TaON/Potassium Poly(Heptazine Imide) Heterostructure for Multifunctional Environmental Remediation

Abstract

Tantalum oxynitride (TaON) has recently attracted much attention due to its excellent performance as a semiconductor. However, its shortage in separation of photogenerated charges hinders the wide application, which, fortunately, can be made up by forming heterojunctions with other photocatalysts. In this study, the rational design of an inorganic‐organic TaON/potassium poly (heptazine imide) (KPHI) heterojunction is reported to separate the photo charges on the two sides of this dyadic structure. The incorporation of 20 wt.% TaON into KPHI resulted not only in H2 generation but also in a wider set of environmental remediation applications under visible light, including Cr(VI) reduction and degradation of otherwise resilient antibiotics. 20TaON/KPHI effectively reduced 17.5 ppm Cr(VI) solution in 35 min under low‐power blue light irradiation with a rate constant which is ≈6 and 30 times higher than that of pristine KPHI and TaON, respectively. Moreover, the composite demonstrated a 2‐ and 40‐fold increase in H2 evolution rate in comparison to pure KPHI and TaON, respectively. This remarkable enhancement in photocatalytic activity is ascribed to the efficient electron‐hole separation and formation of an effective Z‐scheme heterojunction. This work offers a new paradigm for designing efficient photocatalytic systems for environmental applications under low‐power LED and natural sunlight.

Metal Poly(heptazine imides) as Multifunctional Photocatalysts for Solar Fuel Production

“…[23] In contrast, ionic MPHIs generally show 10-to 100-fold increase in H 2 evolution rates relative to melon-like carbon nitrides under identical conditions. [43,[64][65][66][67][68][69][70][71] Just like in other carbon nitrides, various modification strategies for boosting the photocatalytic performance of PHI materials have been explored such as molecular structure engineering, nanostructure design and building heterojunction. In this regard, Zhang et al described a PHI material (CN-OA-m) produced through the co-condensation of urea and oxamide, followed by postcalcination in molten salt.…”