suffer from the relatively poor charge conductivity and the serious recombination of photogenerated charge carriers. [12,13] Considering all these points, more efforts have been devoted to transition metal sulfide photocatalysts, among which CdS shows outstanding properties. [14,15] CdS possesses a bandgap of about 2.4 eV and can utilize a large fraction of the visiblelight irradiation. [16,17] Moreover, CdS has a much more negative conduction band minimum than the redox potential of the water reduction reaction, which provides a large overpotential for the fast reaction kinetics. [18,19] Therefore, rational design of advanced structures for CdS photocatalysts would be an effective approach to realize high-efficiency photocatalytic water reduction. [20] Hollow-structured photocatalysts show distinct advantages for solar energy conversion reactions. [21] Large surface areas and abundant active sites would be provided by hollow structures to promote the photocatalytic reactions. [22] Besides, the thin shells could reduce the distance for the transfer of photogenerated charge carriers. [23] The light scattering effect can be 2004561 (2 of 6) www.advmat.de www.advancedsciencenews.com 2004561 (5 of 6) www.advmat.de www.advancedsciencenews.com cages. The developed synthetic strategy may provide new inspirations for the design and construction of high-performance photocatalysts with advanced structures for solar-to-chemical energy conversion.