▎ 摘　　要

NOVELTY - Preparation of metal oxide loaded graphene quantum dot composite catalyst involves (s1) dispersing 1,3, 6-trinitropyrene in surface termination source solution, heating using Teflon(RTM: PTFE) lined autoclave, filtering, drying to obtain metal oxide loaded graphene quantum dots (M-GQDs), (s2) adding graphene oxide to absolute ethanol, adding dibutyltin dilaurate, stirring, centrifuging, drying to obtain tin oxide nanosheets, (s3) dispersing nanosheets in deionized water, ultrasonically treating to obtain tin oxide suspension, adding M-GQDs solution to the suspension, stirring, heating, cooling, centrifuging, washing and drying to obtain tin oxide/ graphene quantum dot composite catalyst. The surface termination source is nitrogen source, oxygen source or sulfur source. Each 10 mL of M-GQDs solution contains 1-4 mg of M-GQDs. Each 60 mL tin oxide suspension contains 50-100 mg tin oxide nanosheets. The mass ratio of tin oxide nanosheets to M-GQDs is 10-100:1. USE - Preparation of metal oxide loaded graphene quantum dot composite catalyst used as catalytic material for electrocatalytic reduction of carbon dioxide (claimed). ADVANTAGE - The method provides metal oxide loaded graphene quantum dot composite catalyst with adjustable catalytic activity. DETAILED DESCRIPTION - Preparation of metal oxide loaded graphene quantum dot composite catalyst involves (s1) dispersing 3-4 g 1,3, 6-trinitropyrene in every 600 mL of 0.2-0.4 mol/L surface termination source solution, ultrasonically treating for 1-2 hours, transferring the suspension into Teflon(RTM: PTFE) lined autoclave, heating at 180-200℃ for 10-20 hours, cooling, filtering, dialyzing in a dialysis bag for 2-4 days, drying to obtain metal oxide loaded graphene quantum dots (M-GQDs), (s2) adding 50-150 mg graphene oxide to every 200 mL of absolute ethanol, ultrasonically treating for 0.5-1.5 hours, adding 0.5-5.0 mmol dibutyltin dilaurate (DBTDL) to every 100 mg of graphene oxide mixed solution using pipette, stirring at 600-800 rpm for overnight, centrifuging at 7000-10000 rpm and washing with ethanol for 4-5 times to remove excess DBTDL, putting into a muffle furnace at 450-500℃ after drying for overnight and keeping for 2-4 hours to obtain tin oxide nanosheets, (s3) dispersing the tin oxide nanosheets in deionized water, ultrasonically treating for 1-1.5 hours to obtain tin oxide suspension, adding the M-GQDs solution to the tin oxide suspension, vigorously stirring for 1-3 hours at room temperature to obtain a mixed solution, transferring the mixed solution into the Teflon (RTM: PTFE) lined autoclave, heating at 160-200 for 5-8 hours, cooling to room temperature, centrifuging the obtained suspension with deionized water and absolute ethanol, washing and vacuum drying to obtain tin oxide/ graphene quantum dot composite catalyst. The surface termination source is nitrogen source, oxygen source or sulfur source. Each 10 mL of M-GQDs solution contains 1-4 mg of M-GQDs. Each 60 mL tin oxide suspension contains 50-100 mg tin oxide nanosheets. The mass ratio of tin oxide nanosheets to M-GQDs is 10-100:1.