FULL PAPER © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim (1 of 9) 1601190 wileyonlinelibrary.com Exceptional Visible-Light-Driven Cocatalyst-Free Photocatalytic Activity of g-C 3 N 4 by Well Designed Nanocomposites with Plasmonic Au and SnO 2 Amir Zada, Muhammad Humayun, Fazal Raziq, Xuliang Zhang, Yang Qu, Linlu Bai, Chuanli Qin, Liqiang Jing,* and Honggang Fu* Dr. A. Zada, Dr. M. Humayun, Dr. F. Raziq, Dr. X. Zhang, Dr. Y. Qu, Dr. L. Bai, Dr. C. Qin, Prof. L. Jing, Prof. H. Fu Key Laboratory of Functional Inorganic Material Chemistry (Heilongjiang University) Ministry of Education School of Chemistry and Materials Science International Joint Research Center for Catalytic Technology Harbin 150080, P. R. China E-mail: jinglq@hlju.edu.cn; fuhg@vip.sina.com DOI: 10.1002/aenm.201601190 proven to be one of the most excellent pho- tocatalysts for H 2 evolution through water splitting. However, due to its wide band gap of 3.2 eV, TiO 2 can only be excited by ultraviolet radiation, which comprises only 4% of the incoming solar light to the earth. [5] To efficiently utilize the visible light, development of visible-light active photocatalysts is highly desired. Among widely investigated photocatalysts, such as oxides, sulfides and nitrides, g-C 3 N 4 (CN) has attracted great attention because of its suitable band gap (2.7 eV) and favorable chemical stability. [6–9] However, poor vis- ible-light absorption (<470 nm) and high photogenerated charge recombination limit its practical photocatalytic applica- tions. [10] Therefore, it is much meaningful to develop feasible strategies to enhance the visible-light absorption and charge separation for improving photocatalytic activity of CN. As for extending visible-light absorp- tion of CN, doping nonmetallic elements (B, P, S, I) is an effective modification method comprehensively adopted. [11–14] Besides, nanosized noble metals, such as gold (Au) and silver (Ag), have recently been recognized as a new class of effective media suitable for harvesting solar energy benefiting from their high optical absorption over a wide range of solar spectrum based on the localized surface plasmon reso- nance (SPR) effect. [15–18] Therefore, utilizing the SPR effect, noble metals have become another feasible option as modifier for wide band gap oxides to expand the visible-light absorp- tion for efficient photocatalysis. [19–22] Au not only takes obvious advantages among noble metals in extending the visible-light absorption through its SPR effect but also has strong resistance to corrosion and oxidation in moist air. [23,24] However, the works relevant to the Au modified CN have seldom been reported until now. Moreover, the charge transfer mechanism in the fab- ricated SPR-assisted photocatalytic systems is still ambiguous. Therefore, it is worthy to investigate the utilization of the SPR property of Au to improve the visible-light activity of CN. Another way to improve the photocatalytic activity of CN is to promote its charge separation. Constructing heterojunctions In this work, plasmonic Au/SnO 2 /g-C 3 N 4 (Au/SO/CN) nanocomposites have been successfully synthesized and applied in the H 2 evolution as photocatalysts, which exhibit superior photocatalytic activities and favorable stability without any cocatalyst under visible-light irradiation. The amount- optimized 2Au/6SO/CN nanocomposite capable of producing approximately 770 μmol g -1 h -1 H 2 gas under λ > 400 nm light illumination far surpasses the H 2 gas output of SO/CN (130 μmol g -1 ), Au/CN (112 μmol g -1 h -1 ), and CN (11 μmol g -1 h -1 ) as a contrast. In addition, the photocatalytic activity of 2Au/6SO/CN maintains unchanged for 5 runs in 5 h. The enhanced photo- activity for H 2 evolution is attributed to the prominently promoted photogen- erated charge separation via the excited electron transfer from plasmonic Au (≈520 nm) and CN (470 nm > λ > 400 nm) to SO, as indicated by the surface photovoltage spectra, photoelectrochemical I–V curves, electrochemical impedance spectra, examination of formed hydroxyl radicals, and photocur- rent action spectra. Moreover, the Kelvin probe test indicates that the newly aligned conduction band of SO in the fabricated 2Au/6SO/CN is indispen- sable to assist developing a proper energy platform for the photocatalytic H 2 evolution. This work distinctly provides a feasible strategy to synthesize highly efficient plasmonic-assisted CN-based photocatalysts utilized for solar fuel production. 1. Introduction Solar production of H 2 by semiconductor photocatalysis has become one of the most promising methods to store solar energy in clean chemical fuels since it is recognized to be a “green” technology with feasibility. [1–4] To date, TiO 2 has been Adv. Energy Mater. 2016, 1601190 www.MaterialsViews.com www.advenergymat.de