Cocl2 6h2o

FeCl₂ 4H₂O, CoCl₂ 6H₂O, K₃(Co(CN)₆), and dilute hydrochloric acid were brought from Sinopharm Chemical Reagent Co., Ltd. (Shanghai, China), Furan methylamine (FMA), ethanol, and chloroform were provided by Aladdin (Shanghai, China). Anthracite coal was produced at the Tianhushan Coal Mine in Fujian Province (Quanzhou, Fujian Province, China).

Ti₃AlC₂ was purchased from Forsman Technology (Beijing) Co., LTD (Beijing, China). CoCl₂·6H₂O, H₂O₂ and sodium acetate were purchased from Sinopharm Chemical Reagent Co., Ltd. (Shanghai, China). Glucose and TMB were purchased from Aladdin Reagents Co., Ltd. (Shanghai, China). Acetic acid was purchased from Tianjin Tianli Chemical Reagent Co., Ltd. (Tianjin, China). Glucose oxidase (GOX), Tris-HCl, sodium alginate (SA) and terephthalic acid were purchased from Shanghai Macklin Biochemical Co., Ltd. (Shanghai, China). All chemical reagents were of analytical grade and used without further purification.

Substrates 1a (acrylonitrile), 1b (isobutyronitrile), 1c (pentanenitrile), 1d (hexanenitrile), 1e (2-cyanopyrazine), 1f (3-cyanopyridine), 1g (benzonitrile), 1h (cinnamonitrile), 1i (1-naphthonitrile), 1j (thiacloprid), 1k (toyocamycin) and the corresponding amides were purchased from Macklin Co., Ltd (Shanghai, China). Tryptone and yeast extract were purchased from Thermo Fisher Scientific (Waltham, MA, USA). NaCl, KCl, Na₂HPO₄·12H₂O, K₂HPO₄, KH₂PO₄, NaOH, and CoCl₂·6H₂O were obtained from Sinopharm Chemical Reagent Co., Ltd (Shanghai, China). Kanamycin, dithiothreitol, and isopropyl β-d-thiogalactoside (IPTG) were purchased from Sangon Biotech (Shanghai, China). Desthiobiotin was purchased from Sigma-Aldrich (St. Louis, MO, USA). Other commercial reagents like standards and solvents were purchased from Aladdin Reagents (Shanghai, China), Macklin (Shanghai, China), Takara (Dalian, China), and Sinopharm Chemical Reagent Co., Ltd, respectively.

Synthesis of CoS@rGO 0.8 g of CH₃CSNH₂ and various amount of CoCl₂·6H₂O (Sinopharm Chemical Reagent Co., Ltd) were dissolved in 14 mL of DMF/water mixture solvent (1 : 1 v/v). The mixed precursor solution was stirred to form a transparent solution at room temperature using a magnetic stirrer. Then, a columnar rGO was soaked in the solution for 2 days. After that, the solution system was transferred into a Teflon-lined stainless steel autoclave and maintained at 200 °C for 24 h. When it cooled down to room temperature, the product was taken out and rinsed for several times with deionized water and absolute ethanol, respectively. At last, the product was vacuum-dried at 60 °C for 10 h. The amounts of CoCl₂·6H₂O for the preparation of CoS@rGO-1, CoS@rGO-2 and CoS@rGO-3 were 0.4, 0.5 and 0.6 g, respectively.