Electronic Supplementary Material

A facile method to synthesize water-soluble Pd8 nanoclusters unravelingthe catalytic mechanism of p-nitrophenol to p-aminophenol Pan An1,2, Rajini Anumula1, Chaonan Cui1, Yang Liu1, Fei Zhan3, Ye Tao3, and Zhixun Luo1,2 ()

1 Beijing National Laboratory for Molecular Sciences (BNLMS) and State Key Laboratory for Structural Chemistry of Unstable and Stable Species,

Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China 2 University of Chinese Academy of Sciences (UCAS), Beijing 100049, China 3 Beijing Synchrotron Radiation Facility, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China Supporting information to https://doi.org/10.1007/s12274-018-2491-8

 Figure S1 Photographs representing the color change during synthesis of Pd8 NCs.

 Figure S2 The UV-vis absorption spectra of Pd8 NCs after two and five days showing decent stability.

Address correspondence to zxluo@iccas.ac.cn

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 Figure S3 A typical X-ray photoelectron surveys spectrum of the as-prepared Pd8 NCs.

Table S1 Pd L-edge EXAFS curves fitting parameters.

N, coordination number; R, distance between absorber and backscatter atoms; σ2, Debye-Waller factor; ΔE0, inner potential correction accounting for the difference in the inner potential between the sample and the reference compound.

 Figure S4 Normalized Pd K-XANES spectra. The black solid line is experimental results, and the red solid line is the theoretical calculation using full multiple scattering method.

 Figure S5 (a) The absorption spectra for the catalytic reduction of PNP by NaBH4 (red line) and in presence of the ligands of H2SMA (blue line); (b) the square stand for the Ct/C0 with the ligand of H2SMA. C0 stands for the intensity of the absorption at 400 nm initially and Ct is the absorption peak at time.

The internal standard is defined based on UV-vis absorbance of PAP. 10.92 mg PNP was dissolved in 100 ml ultrapure water in a volumetric flask. We took 0.75ml PNP solution and added 2.25 ml ultrapure water to measure the UV-vis spectrum. The intensity of the 300 nm absorption

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peak is 0.542 a.u. Meanwhile, we measure the final intensity of the 300 nm absorption peak in the catalysis reaction is about 0.757 a.u. The solution was diluted 8.89 times. As results, the yield of PNP is estimated to be ~92%.

 Figure S6 The cryo TEM images of Pd clusters (a) and the Pd clusters after catalytic reaction (b).

 Figure S7 The cyclic property of Pd8 NCs in catalyzing PNP-to-PAP.

Table S2 The Pd8 cluster catalysis in comparison with other reported metal catalysts.

 

 Figure S8 The optimized structure of PNP adsorbs on the Pd8 cluster.

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 Figure S9 The natural bond orbital (NBO) donor-acceptor (overlap) interactions between Pd8S8H16 and PNP. The positive and negative donor orbitals are yellow and blue; the positive and negative acceptor orbitals are green and red.

 Figure S10 The proposed reaction pathways of PNP to PAP.

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Table S3 Mulliken charge distribution of Pd8S8H16, PNP, and Pd8S8H16H-PNP.