Selective catalytic reduction of nitrogen oxides with methanol over the (cobalt-molybdenum)/alumina dual catalysts under the diesel methanol dual fuel exhaust conditions

•Methanol plays two prominent roles as the fuel and as the reductant.•The catalytic performance of methanol-SCR was studied on the DMDF engine test bench.•The SCR attains the reductant by either active or passive methanol supply modes.•The DMDF engine with methanol-SCR (cobalt + molybdenum) achieves the ultra-low NOX emissions.