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-GOL), 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-GOL 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-1. Besides, the hybrid showed excellent resistance to both SO2 and O2. Therefore, the present work promoted the high value-added utilization of environment waste, and produced efficient catalyst in favor of sustainable development.