www.afm-journal.de © 2019 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim 1906744 (1 of 29) REVIEW Surface Plasmonic-Assisted Photocatalysis and Optoelectronic Devices with Noble Metal Nanocrystals: Design, Synthesis, and Applications Amir Zada,* Pir Muhammad, Waqas Ahmad, Zahid Hussain, Sharafat Ali, Maaz Khan, Qasim Khan,* and Muhammad Maqbool* The surface plasmon resonance (SPR) of noble metals is known to improve the efficiency of various processes and devices. The photocatalytic process is the production of fuels and storage of solar photons in chemical bonds without imposing harmful threats to the environment. Photovoltaics are other devices utilizing solar energy for electrical energy. Similarly, other optoelec- tronic devices like photodetectors absorb photons and convert it into charges via electron–hole dissociation processes. In contrast, light-emitting optoelec- tronic devices work based on the phenomenon of charge recombination to produce light. All these devices, however, have efficiency limitations, which impede the application of novel functional materials in these devices. A more direct approach is the utilization of noble metals and their complexes, which significantly enhance the efficiencies of these devices by SPR. This article highlights recent works and applications of noble metals by SPR-enhanced photocatalysis for hydrogen evolution from water, CO 2 conversion into useful compounds, and oxidation of hazardous pollutants. In addition, the plasmon- enhancement of optoelectronic devices is summarized. Several possible mech- anisms that have been previously reported in the literature are discussed in this work, with particular emphasis on different features of these mechanisms involving devices that are not highlighted and therefore need more attention. DOI: 10.1002/adfm.201906744 Dr. A. Zada, W. Ahmad, Dr. Q. Khan College of Electronic Science and Technology Shenzhen University Shenzhen, Guangdong 518000, China E-mail: amirzada@awkum.edu.pk; qasim@szu.edu.cn Dr. A. Zada, Prof. Z. Hussain, Dr. S. Ali Department of Chemistry Abdul Wali Khan University Mardan 23200, Pakistan Dr. P. Muhammad Henan-Macquarie University International Joint Center for Biomedical Innovation School of Life Sciences Henan University Kaifeng, Henan 475004, China Prof. M. Khan Pakistani Institute of Nuclear Science and Technology Islamabad 44000, Pakistan Prof. M. Maqbool Department of Physics and Health Physics University of Alabama at Birmingham Birmingham, AL 35294, USA E-mail: mmaqbool@uab.edu taken by plants and indirectly by animals for their reproduction and survival. The photosynthesis process uses H 2 O and CO 2 as raw materials to produce hydrocarbons and release oxygen with the help of solar photons [1] and thus benefitting both ani- mals and plants from each other through this way. [1,2] Production of hydrogen from water using semiconductor photocatalysts takes advantage of the inexhaustibility and envi- ronment-friendly nature of solar energy photons shower on earth. Hydrogen (H 2 ), being a small molecule, can store a huge energy flux in its covalent bonds (142 MJ kg −1 ) as compared to organic fuels. That is why it is accepted as the most talented alternative to hydrocarbons in the future. Photocatalytic and photovoltaic pro- cesses are the two alternatives to capture and store this endless and diffuse energy in the form of chemical bonds in different molecules. Under the solar irradiation, photocatalysts directly convert H 2 O into H 2 and O 2 gases, reduce CO 2 into the fuels and other valuable chemicals, and causing to degrade pollutants into H 2 O and CO 2 without imposing any threat to the environment while photovoltaic cells convert solar energy directly into electricity. [3] However, the evolution of H 2 from water is not an easy process and involves several com- plicated steps as shown in Figure 1. During photocatalysis for H 2 evolution, solar photon absorption promotes electron from The ORCID identification number(s) for the author(s) of this article can be found under https://doi.org/10.1002/adfm.201906744. 1. Introduction Life without energy is not possible, and all living organisms need energy from a natural source like the sun. The inexhaust- ible energy showered by the sun is converted into chemical energy with the help of natural photosynthesis via directly Adv. Funct. Mater. 2019, 1906744