Twin BiSbO4 nanoseeds with {0 1 0}-exposed facets: Facile synthesis and excellent photocatalytic degradation of DDT in highly and long-term contaminated soil

•BiSbO4 nanobundles were synthesized by a facile template-free hydrothermal reaction.•BiSbO4 nanobundles containing twin nanoseeds enclosed by exposed {010} facets.•The total DDT photodegradation efficiency of the twin BiSbO4 is greatly enhanced.•Boosted photoactivity is due to both {010}-exposed facets and twin structure.