To realize surfactant-free synthesis of biomass-derived hollow mesoporous carbon spheres and their derivatives, choice of synthetic methodology and carbon precursor is crucial. Herein, a brand-new hollow mesoporous carbon sphere (HMCS) is first synthesized from 8-quinolinol modified chitosan via an in situ stober templating approach without surfactant followed by pyrolysis and alkali washing. The resultant HMCS is uniform, and shows a cavity size of 417 nm, a shell thickness of 5 nm, and a narrow mesopore size distribution centered at 3.9 nm. The HMCS is then upgraded by encapsulation of a single Au nanocrystal (NC) into the void of HMCS to form a yolk-shell architecture, YS-Au@HMCS. Its cavity size and shell thickness are decreased to 187 and 3 nm, while the mesopore size is increased to 4.3 nm, the surface area (215 m(2) g(-1)) and mesoporosity (74.7%) are triple and twice that of HMCS, respectively, just by halving the delay time of carbon source addition. Owing to the unique hollow interiors and mesopores, as well as their synergism with the encapsulated Au NCs, the elaborately fabricated YS-Au@HMCS exhibits appealing catalytic performances towards the deposal of sewage. It delivers a large activity factor of 34.32, 13.29 and 0.05 s(-1) g(-1) in the reduction of 4-nitrophenol and methylene blue using sodium borohydride, and in the photodegradation of methylene blue under visible light irradiation, respectively. These advances shed new light on the synthesis of hollow mesoporous carbon spheres and the designed synthesis of functional carbon materials with versatile applications. (C) 2018 Elsevier Inc. All rights reserved.