The photocatalytic activity of a CdS/ETS-4 composite for hydrogen production from water under visible light irradiation (lambda > 420 nm) was investigated. It is found that nano-sized US particles embedded in ETS-4 zeolite nano-pores showed stable photocatalytic activity in an aqueous solution containing Na2S and Na2SO3 electron donors and the energy conversion efficiency (ECE) was improved by combining CdS with ETS-4. The results suggest that the encapsulation of CdS in ETS-4 zeolite is effective for improving the activity as well as the stability of Us. (C) 2004 Elsevier B.V. All rights reserved.