TiO1.8 with lattice H for effective electrocatalytic nitrogen fixation

Titanium dioxide (TiO2) is widely used as a representative transition metal oxides (TMOs) catalyst for electrocatalytic nitrogen reduction reaction (NRR). However, the low stability, low selectivity, low ammonia (NH3) yield and high overpotential of TiO2 towards NRR strongly restricted its application in NRR. Here, we firstly add H to the lattice to synthesize a black TiO2−x with oxygen vacancies (OVs) (B-TiO1.8) for electrocatalytic NRR. After we optimized the amount of H and OVs, the NH3 yield and stability can achieve 31.6 μg h−1 mgcat−1 and 100 h at − 0.1 V (vs. RHE), respectively, the faradaic efficiency (FE) can achieve 47.7% at 0 V (vs. RHE). In situ FTIR / ESR / XPS / TPD illustrate that OVs can promote the adsorption and activation of nitrogen (N2), and lattice H can increase the number of OVs and stabilize them, suppress the hydrogen evolution reaction (HER) and promote the hydrogenation of N2. [Display omitted] •TiO2−x with lattice H is synthesized for the first time.•The lattice H can increase the number of OVs, stabilize the OVs.•The lattice H can suppress HER and promote hydrogenation of N2 process.•In situ FTIR / ESR / XPS / TPD illustrate the synergistic promotion of lattice H and OVs in electrocatalytic NRR.