Feyie Endale Kebede, Zereffa Enyew Amare, Tadesse Aschalew, Goddati Mahendra, Noh Daegwon, Oh Eunsoon, Tufa Lemma Teshome, Lee Jaebeom
Department of Applied Chemistry, Adama Science and Technology University, P.O. Box: 1888, Adama 1888, Ethiopia.
Department of Chemistry, Chungnam National University, Daejeon 34134, Republic of Korea.
ACS Omega. 2024 Jun 17;9(26):28463-28475. doi: 10.1021/acsomega.4c02414. eCollection 2024 Jul 2.
The discharge of toxic dye effluents from industry is a major concern for environmental pollution and toxicity. These toxic dyes can be efficiently removed from waste streams using a photocatalysis process involving visible light. Due to its simple synthesis procedure, inexpensive precursor, and robust stability, graphitic carbon nitride (g-CN, or CN) has been used as a visible light responsive catalyst for the degradation of dyes with mediocre performance because it is limited by its low visible light harvesting capability due to its wide bandgap and fast carrier recombination rate. To overcome these limitations and enhance the performance of g-CN, it was coupled with a narrow bandgap copper tin sulfide (CTS) semiconductor to form a p-n heterojunction. CTS and g-CN were selected due to their good stability, low toxicity, ease of synthesis, layered sheet/plate-like morphology, and relatively abundant precursors. Accordingly, a series of copper tin sulfide/graphitic carbon nitride nanocomposites (CTS/g-CN) with varying CTS contents were successfully synthesized via a simple two-step process involving thermal pyrolysis and coprecipitation for visible-light-induced photocatalytic degradation of methyl orange (MO) dye. The photocatalytic activity results showed that the 50%(wt/wt) CTS/g-CN composite displayed a remarkable degradation efficiency of 95.6% for MO dye under visible light illumination for 120 min, which is higher than that of either pristine CTS or g-CN. The improved performance is attributed to the extended light absorption range (due to the optimized bandgap), effective suppression of photoinduced electron-hole recombination, and improved charge transfer that arose from the formation of a p-n heterojunction, as evidenced by electrochemical impedance spectroscopy (EIS), photocurrent, and photoluminescence results. Moreover, the results of the reusability study showed that the composite has excellent stability, indicating its potential for the degradation of MO and other toxic organic dyes from waste streams.
工业排放的有毒染料废水是环境污染和毒性的主要担忧来源。这些有毒染料可通过涉及可见光的光催化过程从废水中有效去除。由于其合成过程简单、前驱体廉价且稳定性强，石墨相氮化碳（g-CN，或CN）已被用作可见光响应催化剂来降解染料，但其性能一般，因为其宽带隙导致可见光捕获能力低且载流子复合速率快。为克服这些限制并提高g-CN的性能，将其与窄带隙的硫化铜锡（CTS）半导体耦合形成p-n异质结。选择CTS和g-CN是因其稳定性好、毒性低、易于合成、具有层状片/板状形态以及前驱体相对丰富。因此，通过热解和共沉淀的简单两步法成功合成了一系列不同CTS含量的硫化铜锡/石墨相氮化碳纳米复合材料（CTS/g-CN），用于可见光诱导的甲基橙（MO）染料光催化降解。光催化活性结果表明，50%（wt/wt）的CTS/g-CN复合材料在可见光照射120分钟下对MO染料的降解效率高达95.6%，高于原始CTS或g-CN。性能的提高归因于光吸收范围的扩展（由于带隙优化）、光生电子-空穴复合的有效抑制以及p-n异质结形成带来的电荷转移改善，电化学阻抗谱（EIS）、光电流和光致发光结果证明了这一点。此外，可重复使用性研究结果表明该复合材料具有出色的稳定性，表明其在降解废水中的MO和其他有毒有机染料方面具有潜力。
