Highly efficient manganese oxide decorated graphitic carbon nitrite electrocatalyst for reduction of CO2 to formate

• Published in: Catalysis today 2021-06, Vol.370, p.104-113
• Main Authors: Mulik, Balaji B., Munde, Ajay V., Bankar, Balasaheb D., Biradar, Ankush V., Sathe, Bhaskar R.
• Format: Article
• Language: English
• Subjects: Carbon dioxide; Electrochemical/chemical hydrogenation; Energy and environmental issues; Faradic efficiency; Formate formation; Renewable energy
• ISSN: 0920-5861; 1873-4308
• DOI: 10.1016/j.cattod.2020.12.008

The MnO2 decorated gC3N4 nanocomposite synthesized by precipitation followed by calcination method for electrochemical and chemical hydrogenation of CO2. This proposed system applies to various industries and to solve the energy and environmental issues. [Display omitted] •An economical fabrication of manganese oxide (MnO2) supported on graphitic carbon nitride (g-C3N4).•Ultralow potential for hydrogenation of CO2 with Faradic efficiency of 65.28% at −0.52 V Vs RHE.•Ultra-high current/potential stability for electrochemical and chemical hydrogenation of CO2.•Envisioned and progressive catalysts for CO2 reduction. Herein, an effective electrocatalyst exploiting non-noble metal oxide-containing of manganese oxide (MnO2) supported on graphitic carbon nitride (g-C3N4) for reduction of CO2 over a wide range of potential. The MnO2 decorated g-C3N4 nanocomposite was synthesized by precipitation, followed by calcination to attain uniform distribution of the MnO2. The MnO2 was found α-MnO2 crystal structure with a size of ∼0.5–2 nm having interlinear lattice spacing of 0.243 nm seen on the layer of g-C3N4 (50−100 nm). The high defective sites observed on MnO2/g-C3N4 (ID/IG) is 1.91 than pristine g-C3N4 (ID/IG) is 0.054. The core spectrum analysis of XPS showed N, C, O and Mn atoms in the as-synthesized composite. The electrocatalysts were executed for electrocatalytic hydrogenation of CO2 at lower onset potential of −0.14 V vs. RHE into C1 products having Faradaic efficiencies (FE) of 8, 47.45 and 65.28% at an applied potential of −0.14, −0.34 and −0.54 V vs. RHE, respectively. The catalyst has further used for the chemical hydrogenation of CO2, and the good yield of formic acid was 9603.28 μmol obtained. The enrichment of the electrocatalytic activities was observed due to the synergetic effect of both MnO2 and g-C3N4. This methodology will be applicable for industrial applications and it will help control environmental issues.