Cobalt Porphyrazine Supported on SnO₂ with Oxygen Vacancies for Boosting Photocatalytic Aerobic Oxidation of Glucose to Organic Acids in an Aqueous Medium

Abstract

There is increasing interest in the production of value-added chemicals by oxidizing glucose with the aid of photocatalysis in an aqueous medium. Herein, a new SnO2-OVs/CoPz composite was prepared through cobalt tetra­(2,3-bis­(butylthio)­maleonitrile)­porphyrazine (CoPz) supported on SnO2 with oxygen vacancies (SnO2-OVs), and the as-prepared SnO2-OVs/CoPz composite exhibited strong visible-light absorption and excellent charge separation efficiency. The SnO2-OVs/CoPz composite possessed a stronger adsorption ability toward glucose, while the composite possessed a moderate adsorption ability toward organic acid. Therefore, the SnO2-OVs/CoPz composite showed excellent photocatalytic activity for oxidizing glucose to organic acid in an aqueous medium, using atmospheric dioxygen as an oxidant under simulated sunlight irradiation. Various kinds of organic acids including glucaric acid, gluconic acid, and formic acid were acquired through this composite photocatalytic system. The synergy of SnO2-OVs and CoPz accelerated the glucose oxidation. The total selectivity toward the above three organic acids can reach up to 81.5% at 43.6% glucose conversion after reacting for 3 h under optimal conditions, especially 28.5% selectivity toward glucaric acid was acquired in an aqueous medium. The effects of various active species on glucose oxidation were further revealed by scavenger experiments and ESR detections. This work provides a strategy to fabricate new photocatalysts for efficient organic transformation.

Synthesis of NiO-, CuO-, and Co3O4-Decorated Carbon Nanotubes for Electrochemical Detection and Conversion of Glucose

“…As shown in Figure S9, six compounds were identified and their concentrations were calibrated by HPLC standard curves. After a 4 h electrolysis at 1.666 V, the conversion of glucose is 56.5, 43.2, and 53.9%, using NiO/CNTs, CuO/CNTs, and Co 3 O 4 /CNTs, respectively, which is comparable with the conversion rates reported in most works. ,, It should be pointed out that the conversion of glucose can be further increased by extending electrolysis time and optimizing potential. The product distributions of glucose oxidation by the three materials at 1.666 V were compared.…”

“…After a 4 h electrolysis at 1.666 V, the conversion of glucose is 56.5, 43.2, and 53.9%, using NiO/CNTs, CuO/CNTs, and Co 3 O 4 /CNTs, respectively, which is comparable with the conversion rates reported in most works. 20,46,47 It should be pointed out that the The effects of potentials on the product distribution of glycose oxidation over the catalysts were investigated. The selectivity of GNA increases with increasing applied potential, indicating that the higher potentials are favorable for the selective conversion of glucose to GNA.…”

Selective oxidation of biomass-derived carbohydrate monomers

“…Recycling tests confirmed that the catalyst did not lose significant activity (44.6% conversion) or selectivity (18.6% GA selectivity) after five cycles. Testing of a CoPz-modified SnO 2 engineered to have more oxygen vacancies 101 gave similar results (Table 3).…”

“…Recycling tests confirmed that the catalyst did not lose significant activity (44.6% conversion) or selectivity (18.6% GA selectivity) after five cycles. Testing of a CoPz-modified SnO 2 engineered to have more oxygen vacancies 101 gave similar results (Table 3). Bai et al 102 went one step further and synthesized a completely metal-free photocatalyst based on graphitic carbon nitride (g-C 3 N 4 ), modified with NaBH 4 and chlorin e6.…”

Oxygen Vacancy Induced Atom-Level Interface in Z-Scheme SnO2/SnNb2O6 Heterojunctions for Robust Solar-Driven CO2 Conversion

“…The absorption peaks at 675 and 640 cm –1 are ascribed to the internal vibration of Nb–O in the NbO 6 octahedron and Sn–O, respectively. The introduction of O v causes the splitting (650 and 570 cm –1 ) of Sn–O peaks in O v -SnO 2 , originating from the asymmetric stretching vibration of the O v -Sn–O bond. − In O v -SnO 2 /SNO composites, the Sn–O cleavage peak at 570 cm –1 is weakened and a wide peak within 510–760 cm –1 is observed due to the formation of Sn–O–Nb bonds. , Besides, a weak peak at 1420 cm –1 is observed in O v -SnO 2 and O v -SnO 2 /SNO, which is mainly caused by the conversion of CO 2 into HCO 3 – anion by surface O v as active sites . As seen from the Raman spectra in Figure c, the sharp peak at 634 cm –1 of O v -SnO 2 has originated from the in-plane O v in SnO 2 , which is weakened in O v -SnO 2 /SNO, due to the bonding effect among Nb in SnNb 2 O 6 and unsaturated O in O v -SnO 2 .…”