Electrocatalytic activity analysis of vinegar residue-based heteroatom-doped carbon quantum dots integrated on vertically aligned graphene arrays for hydrogen evolution reaction

Carbon-based materials are considered cost-effective electrocatalysts for hydrogen evolution reaction (HER). Here we design the heteroatom-doped carbon quantum dots (CQDs) loaded on vertical graphene (VG) as HER catalyst by density functional theory (DFT). And heteroatoms (B/N/P/S)-doped CQDs is synthesized with vinegar residue as the carbon source, which are integrated on VG as HER electrocatalysts. The results of electrochemical measurements are consistent with the DFT calculations. The heteroatom of CQDs in heteroatom-doped CQDs loaded on VG (CQDs-VG) is the leading active site in the HER process, which increases the catalytic potential of VG. The VG substrate increases the electron density of the heteroatom, which decreases the energy barrier and improves the catalytic activity. The N-doped catalyst shows the best potential in the HER process. This work contributes for the development of carbon based cost-effective electrocatalysts for water-splitting.