In summary, a series of CdS and CdS/CNTs photocatalysts
with different crystal size, crystallinity as well as crystal phase
were prepared in alkalinity controlled condition. It was found
that highest H2 production rate of CdS was 794.6 mmol h1 g1
obtained when 0.06 mol NaOH were used in CdS preparation.
Hexagonal phase which was controlled by NaOH was the most
active site. According to the different methods for preparing
CdS/CNTs photocatalysts, we found that appropriate alkalinity
and mild reaction environment is essential to composition,
and the photocatalytic activity can be further improved
to 1.771 mmol h1 g1 by using a kind of two-step method. The
activity on this optimized CdS/CNTs photocatalyst can be
accelerated again by loading NiS cocatalyst, achieving
12.13 mmol h1 g1 when 0.75% NiS were loaded