Understanding and application of an electroplating sludge-derived catalyst with an active texture for improved NO reduction.

Industrial sludge has been shown to be a valuable source of transition metals and to be effective in NO reduction. This research has further revealed a characteristic texture (O-Me-C) that promotes effective NO reduction and supports its existence in a sludge-derived catalyst. HRTEM exhibited that the O-Me-C consisted of multi-metal-oxide core, carbon shell and their binding interfaces. Furthermore, pre-treatment of the sludge with aromatic containing wastewater produced a more active texture (O-Me-GO), characterized by the presence of multi-metal-oxide core, graphene oxide-like carbon and highly active interfaces (EELS, Mössbauer and Raman). As a result, the hybrid with O-Me-GO exhibited enhanced activity and was able to remove >45% of NO (1000 ppm) at 200 °C and >99% at 400 °C over a much longer period (from 25 to 180 min) with an hourly gas space velocity of 14,400 h. Besides, the hybrid showed excellent resistance to both SO and O. Therefore, the present work promoted the high value-added utilization of environment waste, and produced efficient catalyst in favor of sustainable development.