Catalytic hydropyrolysis of lignin using NiMo-doped catalysts: Catalyst evaluation and mechanism analysis

•A NiMo-doped catalyst with optimal Ni/Mo ratio and carrier led to hydrocarbon bio-oil with low selectivity of polyaromatics and methane.•Two coefficients were proposed to qualitatively evaluate the activity of NiMo catalysts.•The effect of hydrogen pressure on catalytic activity of NiMo-doped catalysts was illustrated.•The synergistic mechanism of Ni and Mo was studied during the catalytic hydropyrolysis of lignin.•The evolution mechanism of lignin hydropyrolysis volatiles over NiMo/ZrO2 was proposed.