Prof. Jun YANG was born in Hebei, China, in 1972. He received his Ph.D. in Chemical and Biomolecular Engineering in 2006 from the National University of Singapore (with Professor Jim Yang LEE). After postdoctoral research at Boston College and University of Toronto with Prof. Shana O. Kelley, he joined the Institute of Bioengineering and Nanotechnology, Singapore, in 2007. In 2010, he moved to the Institute of Process Engineering, Chinese Academy of Sciences, as the group leader of Materials for Energy Conversion and Environmental Remediation (MECER). He is also a joint professor of School of Materials Science and Opto‐Electronic Technology, University of Chinese Academy of Sciences. His main research interests include electrocatalysis, nanocomposites for energy conversion, synthesis and application of novel nanocrystalline materials, and separation techniques.

Nanocomposites consisting of noble metals and semiconductors or metal oxides represent an important type of heterogeneous nanostructures, which often exhibit improved physical and chemical properties than those of isolated individual nanoparticles. The enhancement might be attributed to the synergistic effect that occurs at the permanent inorganic interface of metal and semiconductor/metal oxide domains in the composite nanoparticles. Over the past two decades, there have been tremendous developments in the high degree of control over nanocomposites in terms of their domain size, morphology, and composition. Naturally, extensive applications emerge in the field of photocatalysis, as nanoscale sections of certain semiconductors or metal oxides combined with appropriate noble metals as cocatalysts could allow the photogenerated charge carriers to separate effectively for performing redox reactions with high efficiency. In addition, noble metal‐based nanocomposites would be particularly useful for electrocatalytic applications. Adjacent domains of semiconductors or metal oxides having different electron affinity and, appropriately, energy‐level alignments could either donate or withdraw electrons from the noble metal domains through the solid‐state interfaces of the nanocomposites, thus inducing the changes of the electron density around the metal atoms. The changes in electron density would tune the catalytic property of noble metals by altering the adsorption/desorption of reactants on the same.

Following the groundbreaking study made by the Banin group in 2004, who demonstrated a solution‐based synthesis of nanohybrids via the selective growth of gold tips on the apexes of hexagonal‐phase CdSe nanorods at room temperature, the efforts of many leading research groups have led to a rich variety of noble metal‐based nanocomposites, e.g. ZnO–Ag, ZnO–Au, ZnO–Au–Ni, CdS–Au, InAs–Au, TiO₂–Ag, TiO₂–Au, Fe₃O₄–Au, α‐Fe₂O₃–Au, Fe₃O₄–Ag, VO₂–Au, MnO–Au, SiO₂–Au, CuO–Ag, Cu₂O–Ag, Cu₂O–Au, CdO–Au, In₂O₃–Au/Ag, CoFe₂O₄–Ag, AgGaO₂–Ag, Bi₂S₃–Au, CdSe–Au, CdTe–Au, CdSe–Ag, Ag₂S–Au, Ag₂S–Ag, AgBr–Ag, Cu₂S–Au, Cu_2−xSe–Au, PbS–Au, PbSe–Au, PbTe–Au, SnS–Au, ZnS–Au, ZnSe, CuInS₂–Au, Cu₂ZnSnS₄–Au, Si–Au, and Pt, Pd, or other noble metal‐based composite nanosystems, by anisotropic growth of noble metals on semiconductor/metal oxides through photo‐ or thermal reduction. The accumulation creates great opportunities and also a tremendous challenge to apply these materials in diverse realms, e.g. optics, energy conversion/storage, and environmental remediation. We therefore prefer to devote this book to summarize the developments of solution‐based methods for the preparation of noble metal‐based nanocomposites and their characterization and potential applications in diverse catalysis so as to provide the readers with a systematic and coherent picture of the field. We hope that through this research effort, one can learn and expect the future progress in synthetic ability would open up access to new breeds of nanomaterials with multiple functionalities, which could enable optical, optoelectronic, magnetic, biomedical, photovoltaic, and specifically catalytic applications with a high level of performance.

The contents benefit greatly from the communications between the authors and colleagues and peers in a number of conferences and forums. We are grateful in particular to our staff/students: Dong Chen, Penglei Cui, Hui Liu, Jianglan Qu, Feng Ye, Junyu Zhong, Yan Feng, Pengfei Hou, Weiwei Hu, Chengyin Li, Jiaqi Li, Danye Liu, Jiayi Tang, and Linlin Xu, Niuwa Yang, and Hong Zhang, who took care of the format of figures and references, went through the details to correct the typos and to clarify many points in the presentation, and got all the copyright permissions. We are also indebted to all our colleagues/collaborators in research laboratories at the National University of Singapore, Boston College, University of Toronto, Institute of Bioengineering and Nanotechnology, and Institute of Process Engineering, Chinese Academy of Sciences. Without their helpful suggestions and valuable contributions, this book would not have been possible. Dr. Lifen Yang at Wiley‐VCH is particularly acknowledged for her initiation of this book. The writing of this book started with the beginning of the new semester and was fulfilled by the end of the summer holidays. The author thanks his wife Lijing Wang and sons Renxiao and Renzhe for their unending love and support and their understanding of why Dad was always not able to enjoy time with them.

September 2018

Jun Yang

Institute of Process Engineering

Chinese Academy of Sciences

University of Chinese Academy of Sciences

Beijing, China

The authors gratefully acknowledge the financial support from the 100 Talents Program of the Chinese Academy of Sciences, National Natural Science Foundation of China (Grant Nos.: 21173226, 21376247, 21476246, 21506225, 21506234, 21573240, 21706265, 21776292), the Center for Mesoscience, Institute of Process Engineering, Chinese Academy of Sciences (COM2015A001), State Key Laboratory of Multiphase Complex Systems, Institute of Process Engineering, Chinese Academy of Sciences (MPCS‐2012‐A‐11, MPCS‐2017‐A‐02), National Natural Science Foundation of Beijing, China (Grant No.: 2173062), the importation and development of High‐Caliber Talents Project of Beijing Municipal Institutions (CIT&TCD201704049), the development of Beijing Excellent Talents Project (2016000026833ZK01), and the Technology Innovation Project of Beijing Municipal Institutions (KM201610020001).