TY - JOUR

T1 - Photocatalytic H2 production and degradation of aqueous 2-chlorophenol over B/N-graphene-coated Cu0/TiO2

T2 - A DFT, experimental and mechanistic investigation

AU - Ombaka, Lucy M.

AU - McGettrick, James D.

AU - Oseghe, Ekemena O.

AU - Al-Madanat, Osama

AU - Rieck genannt Best, Felix

AU - Msagati, Titus A.M.

AU - Davies, Matthew L.

AU - Bredow, Thomas

AU - Bahnemann, Detlef W.

N1 - Funding Information: This work was funded by the Alexander von Humboldt Foundation . Special thanks goes Patrick Bessel for the UV–Vis–NIR analysis. J.D.M. and M.L.D. are grateful for the support of the EPSRC , Welsh Government (Project 80708 ) and Innovate UK for the SPECIFIC Innovation and Knowledge Center ( EP / N020863/1 ). M.L.D. is grateful for the financial support of the EPSRC ( EP/R016666/1 and EP/S001336/1 ). F.R.g.B. thanks the Deutsche Forschungsgemeinschaft ( DFG ), grant CA147/21–1 , projectnumber 322911753 for the financial support. T.B. thanks the Paderborn Center for Parallel Computing for providing computational resources.

PY - 2022/6

Y1 - 2022/6

N2 - Energy and environmental challenges are global concerns that scientists are interested in alleviating. It is on this premise that we prepared boron/nitrogen graphene-coated Cu0/TiO2 (B/N-graphene-coated Cu/TiO2) photocatalyst of varying B:N ratios with dual functionality of H2 production and 2-Chlorophenol (2-CP) degradation. In-situ coating of Cu0 with B/N-graphene is achieved via solvothermal synthesis and calcination under an inert atmosphere. All B/N-graphene-coated Cu/TiO2 exhibit higher photonic efficiencies (5.68%–7.06% at 300 < λ < 400 nm) towards H2 production than bare TiO2 (0.25% at 300 < λ < 400 nm). Varying the B:N ratio in graphene influences the efficiency of H2 generation. A B:N ratio of 0.08 yields the most active composite exhibiting a photonic efficiency of 7.06% towards H2 evolution and a degradation rate of 4.07 × 10−2 min−1 towards 2-chlorophenol (2-CP). Density functional theory (DFT) investigations determine that B-doping (p-type) enhances graphene stability on Cu0 while N-doping (n-type) increases the reduction potential of Cu0 relative to H+ reduction potential. X-ray photoelectron spectroscopy reveals that increasing the B:N ratio increases p-type BC2O while decreasing n-type pyridinic-N in graphene thus altering the interlayer electron density. Isotopic labelling experiments determine water reduction as the main mechanism by which H2 is produced over B/N-graphene-coated Cu/TiO2. The reactive species involved in the degradation of 2-CP are holes (h+), hydroxyl radical (OH•), and O2•-, of which superoxide (O2•-) plays the major role. This work displays B/N -graphene-coated Cu/TiO2 as a potential photocatalyst for large-scale H2 production and 2-CP degradation.

AB - Energy and environmental challenges are global concerns that scientists are interested in alleviating. It is on this premise that we prepared boron/nitrogen graphene-coated Cu0/TiO2 (B/N-graphene-coated Cu/TiO2) photocatalyst of varying B:N ratios with dual functionality of H2 production and 2-Chlorophenol (2-CP) degradation. In-situ coating of Cu0 with B/N-graphene is achieved via solvothermal synthesis and calcination under an inert atmosphere. All B/N-graphene-coated Cu/TiO2 exhibit higher photonic efficiencies (5.68%–7.06% at 300 < λ < 400 nm) towards H2 production than bare TiO2 (0.25% at 300 < λ < 400 nm). Varying the B:N ratio in graphene influences the efficiency of H2 generation. A B:N ratio of 0.08 yields the most active composite exhibiting a photonic efficiency of 7.06% towards H2 evolution and a degradation rate of 4.07 × 10−2 min−1 towards 2-chlorophenol (2-CP). Density functional theory (DFT) investigations determine that B-doping (p-type) enhances graphene stability on Cu0 while N-doping (n-type) increases the reduction potential of Cu0 relative to H+ reduction potential. X-ray photoelectron spectroscopy reveals that increasing the B:N ratio increases p-type BC2O while decreasing n-type pyridinic-N in graphene thus altering the interlayer electron density. Isotopic labelling experiments determine water reduction as the main mechanism by which H2 is produced over B/N-graphene-coated Cu/TiO2. The reactive species involved in the degradation of 2-CP are holes (h+), hydroxyl radical (OH•), and O2•-, of which superoxide (O2•-) plays the major role. This work displays B/N -graphene-coated Cu/TiO2 as a potential photocatalyst for large-scale H2 production and 2-CP degradation.

KW - 2-Chlorophenol degradation

KW - Green energy

KW - Hydrogen production

KW - Metallic copper

KW - Photocatalysis

UR - http://www.scopus.com/inward/record.url?scp=85125574793&partnerID=8YFLogxK

U2 - 10.1016/j.jenvman.2022.114822

DO - 10.1016/j.jenvman.2022.114822

M3 - Article

C2 - 35255324

AN - SCOPUS:85125574793

VL - 311

JO - Journal of Environmental Management

JF - Journal of Environmental Management

SN - 0301-4797

M1 - 114822

ER -