One-Pot Hydrothermal Synthesis of Visible-Light-Responsive MoS2/g-CNO Heterostructures for Organic-Pollutant Degradation

Abstract

MoS2/g-CNO (g-CNO = oxidized graphitic carbon nitride) heterostructures were synthesized by a one-step lowtemperature hydrothermal route. The hydrolysis and oxidation reactions during the hydrothermal synthesis provide a fivefold increase in the surface area of the carbon nitride matrix. The heterostructure formation between MoS2 and the g-CNO matrix induced reduced recombination effects, and 1 wt.-% MoS2/g- CNO composites showed the highest photocatalytic activity to- Introduction Over the past few decades, the widespread industrial release of various organic pollutants has induced deleterious effects on both humans and animals. The traditional methods employed for the degradation of pollutants are expensive, time-consuming, and often produce toxic products that are retained in the effluent. Therefore, a “green” photocatalytic strategy that utilizes solar energy has been considered as an environmentally benign pathway for the removal of organic pollutants.[1] Recently, a host of new developments such as electrochemical water splitting,[2] hydrogen gas production, the reduction of CO2 to CH4,[3] electricity generation from newer photovoltaic cells,[4] and the degradation of organic pollutants[5] have been achieved by exploiting solar energy and by employing photocatalytic technology. The photocatalytic efficiencies of the initially developed metal chalcogenides such as TiO2, ZnO, ZnS, BiVO4, Ag3PO4, CdS, WO3, and TaON have been confined by several factors such as photoexcited electron–hole recombination, negligible absorption in the visible range of the solar spectrum, inferior charge-carrier mobility, improper band-gap alignment, and the [a] Materials Science and Technology Division (MSTD), National Institute for Interdisciplinary Science and Technology, Council of Scientific and Industrial Research (CSIR-NIIST), Thiruvananthapuram 695019, India E-mail: hareesh@niist.res.in http://www.niist.res.in/english/scientists/hareesh-u-s/personal.html [b] R&D Center, Noritake Company LTD, Miyoshi Higashiyama 300, Miyoshi, Aichi 470- 0293, Japan [c] Academy of Scientific and Innovative Research, New Delhi, India Supporting information and ORCID(s) from the author(s) for this article are available on the WWW under http://dx.doi.org/10.1002/ejic.201600232. Eur. J. Inorg. Chem. 2016, 3912–3920 3912 © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim wards the degradation of organic pollutants under visible-light irradiation. Moreover, owing to the presence of groups with negative inductive effects in g-CNO and g-CNO-based composites, the photocatalytic activities were higher than that of bare g-C3N4. Recyclability studies on the synthesized catalysts indicated no loss of efficiency after four cycles. Thus, these MoS2/ g-CNO heterostructures are promising photocatalysts for the degradation of organic pollutants.