{"title":"A strontium doped p–n heterojunction TiO2/Sr–Co3O4 composite for enhanced photocatalytic degradation of MG dye under solar light irradiation","authors":"Debapriya Pradhan, Susanta Kumar Biswal, Rasmirekha Pattanaik, Nibedita Nayak and Suresh Kumar Dash","doi":"10.1039/D4NJ02906B","DOIUrl":null,"url":null,"abstract":"<p >The application of well-tailored semiconducting hybrid composites in purifying contaminated surface water is a greatly sought-after field. TiO<small><sub>2</sub></small>, a prominent photocatalyst with higher band energy, was hybridised with strontium-doped Co<small><sub>3</sub></small>O<small><sub>4</sub></small> nanoparticles for the effective degradation of malachite green (MG) dye under solar light. A TiO<small><sub>2</sub></small>/Sr–Co<small><sub>3</sub></small>O<small><sub>4</sub></small> composite with excellent visible light absorption ability and narrow band gap energy (<em>E</em><small><sub>g</sub></small> = 2.0 eV) was synthesised by applying a simple co-precipitation method. The structural, morphological and optical properties of the synthesized catalyst were analysed through XRD, FE-SEM, EDS, HR-TEM, FTIR, Raman spectroscopy, UV-DRS and surface properties were investigated <em>via</em> BET analysis. The doping of strontium metal on Co<small><sub>3</sub></small>O<small><sub>4</sub></small> (p-type) acted as an electron facilitator to TiO<small><sub>2</sub></small> (n-type) at the p–n hetero-junction of the TiO<small><sub>2</sub></small>/Sr–Co<small><sub>3</sub></small>O<small><sub>4</sub></small> composite, increasing its efficiency towards photo-degradation of MG dye compared to pure Co<small><sub>3</sub></small>O<small><sub>4</sub></small>, TiO<small><sub>2</sub></small>, Sr–Co<small><sub>3</sub></small>O<small><sub>4</sub></small>, and Co<small><sub>3</sub></small>O<small><sub>4</sub></small>–TiO<small><sub>2</sub></small> under solar irradiation. A maximum degradation of 92% occurred at pH 10 with a dye concentration of 20 ppm and catalyst dose of 0.02 g L<small><sup>−1</sup></small> in 60 min under solar irradiation. The photocatalytic degradation of MG dye by TiO<small><sub>2</sub></small>/Sr–Co<small><sub>3</sub></small>O<small><sub>4</sub></small> followed pseudo first-order kinetics. TiO<small><sub>2</sub></small>/Sr–Co<small><sub>3</sub></small>O<small><sub>4</sub></small> exhibited good stability by maintaining 80% degradation of MG dye after five consecutive cycles.</p>","PeriodicalId":95,"journal":{"name":"New Journal of Chemistry","volume":null,"pages":null},"PeriodicalIF":2.7000,"publicationDate":"2024-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"New Journal of Chemistry","FirstCategoryId":"92","ListUrlMain":"https://pubs.rsc.org/en/content/articlelanding/2024/nj/d4nj02906b","RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"CHEMISTRY, MULTIDISCIPLINARY","Score":null,"Total":0}
引用次数: 0
Abstract
The application of well-tailored semiconducting hybrid composites in purifying contaminated surface water is a greatly sought-after field. TiO2, a prominent photocatalyst with higher band energy, was hybridised with strontium-doped Co3O4 nanoparticles for the effective degradation of malachite green (MG) dye under solar light. A TiO2/Sr–Co3O4 composite with excellent visible light absorption ability and narrow band gap energy (Eg = 2.0 eV) was synthesised by applying a simple co-precipitation method. The structural, morphological and optical properties of the synthesized catalyst were analysed through XRD, FE-SEM, EDS, HR-TEM, FTIR, Raman spectroscopy, UV-DRS and surface properties were investigated via BET analysis. The doping of strontium metal on Co3O4 (p-type) acted as an electron facilitator to TiO2 (n-type) at the p–n hetero-junction of the TiO2/Sr–Co3O4 composite, increasing its efficiency towards photo-degradation of MG dye compared to pure Co3O4, TiO2, Sr–Co3O4, and Co3O4–TiO2 under solar irradiation. A maximum degradation of 92% occurred at pH 10 with a dye concentration of 20 ppm and catalyst dose of 0.02 g L−1 in 60 min under solar irradiation. The photocatalytic degradation of MG dye by TiO2/Sr–Co3O4 followed pseudo first-order kinetics. TiO2/Sr–Co3O4 exhibited good stability by maintaining 80% degradation of MG dye after five consecutive cycles.