title: Free-standing iridium and rhodium-based hierarchically-coiled ultrathin nanosheets for highly selective reduction of nitrobenzene to azoxybenzene under ambient conditions.
abstract: The fabrication of atom-layered two dimensional (2D) noble metal nanosheets (NSs) in a face-centered cubic (fcc) structure is of broad scientific and technological importance, yet this remains a challenge due to the intrinsic cubic symmetry and high surface energy of fcc noble metals. Herein, we report a solid-liquid interface mediated 2D growth method towards the synthesis of hierarchically-coiled ultrathin Ir NSs (thickness <2 nm) and Rh NSs (0.8 nm thick), and bimetallic Ir-Rh NSs (1.2 nm thick) and Pt-Rh NSs (1.2 nm thick) using the benzyl alcohol solvothermal approach. The formation of NSs was attributed to the 2D oriented attachment of tiny seeds through the lateral growth stemming from the abundant defect sites of the seeds produced in the heterogeneous system. The free-standing Ir NSs, Rh NSs and Ir-Rh NSs exhibited high selectivities (from 83.9% to 88.5%) towards the selective reduction of nitrobenzene to azoxybenzene in ethanol at room temperature with 1 atm of hydrogen, because the condensation step of nitrosobenzene (PhNO) and phenylhydroxylamine (PhNHOH) was more exothermic than the dissociation step of Ph-NHOH on the (111) facets of the NSs under alkaline conditions, as indicated by density functional theory (DFT) calculations.
authors.affiliation: Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Rare Earth Materials Chemistry and Applications, PKU-HKU Joint Laboratory in Rare Earth Materials and Bioinorganic Chemistry, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China. ywzhang@pku.edu.cn.
authors.forename: Zhi-Ping
authors.initials: ZP
authors.lastname: Zhang
authors.affiliation: Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Rare Earth Materials Chemistry and Applications, PKU-HKU Joint Laboratory in Rare Earth Materials and Bioinorganic Chemistry, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China. ywzhang@pku.edu.cn.
authors.forename: Xin-Yu
authors.initials: XY
authors.lastname: Wang
authors.affiliation: Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Rare Earth Materials Chemistry and Applications, PKU-HKU Joint Laboratory in Rare Earth Materials and Bioinorganic Chemistry, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China. ywzhang@pku.edu.cn.
authors.forename: Kun
authors.initials: K
authors.lastname: Yuan
authors.affiliation: Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Rare Earth Materials Chemistry and Applications, PKU-HKU Joint Laboratory in Rare Earth Materials and Bioinorganic Chemistry, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China. ywzhang@pku.edu.cn.
authors.forename: Wei
authors.initials: W
authors.lastname: Zhu
authors.affiliation: Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Rare Earth Materials Chemistry and Applications, PKU-HKU Joint Laboratory in Rare Earth Materials and Bioinorganic Chemistry, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China. ywzhang@pku.edu.cn.
authors.forename: Tao
authors.initials: T
authors.lastname: Zhang
authors.affiliation: Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Rare Earth Materials Chemistry and Applications, PKU-HKU Joint Laboratory in Rare Earth Materials and Bioinorganic Chemistry, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China. ywzhang@pku.edu.cn.
authors.forename: Yu-Hao
authors.initials: YH
authors.lastname: Wang
authors.affiliation: Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Rare Earth Materials Chemistry and Applications, PKU-HKU Joint Laboratory in Rare Earth Materials and Bioinorganic Chemistry, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China. ywzhang@pku.edu.cn.
authors.forename: Jun
authors.initials: J
authors.lastname: Ke
authors.affiliation: Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Rare Earth Materials Chemistry and Applications, PKU-HKU Joint Laboratory in Rare Earth Materials and Bioinorganic Chemistry, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China. ywzhang@pku.edu.cn.
authors.forename: Xiao-Yu
authors.initials: XY
authors.lastname: Zheng
authors.affiliation: Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Rare Earth Materials Chemistry and Applications, PKU-HKU Joint Laboratory in Rare Earth Materials and Bioinorganic Chemistry, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China. ywzhang@pku.edu.cn.
authors.forename: Chun-Hua
authors.initials: CH
authors.lastname: Yan
authors.affiliation: Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Rare Earth Materials Chemistry and Applications, PKU-HKU Joint Laboratory in Rare Earth Materials and Bioinorganic Chemistry, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China. ywzhang@pku.edu.cn.
authors.forename: Ya-Wen
authors.initials: YW
authors.lastname: Zhang