Capture and Utilization of CO2 with Morpholine for Effective Photocatalytic N-Formylmorpholine Production.

Converting into high-value-added products represents the most optimal approach to CO2 utilization. The substitution of CO with CO2 as a potential critical material for formamide production is widely regarded as an ideal pathway and has garnered significant attention. However, high temperatures and pressures remain essential for the reaction, exerting a substantial influence on the utilization process. Herein, N-formylmorpholine was creatively synthesized by integrating the capture and solar-driven utilization of CO2 with morpholine. Notably, a remarkable N-formylmorpholine yield of 11433.3 µmol·h-1·g-1 was obtained, surpassing pure MoO3 by an astounding factor of 89.1 with a N-formylmorpholine yield of 63.8 µmol in 6 h, which is an astonishing increase of 57.5 times compared to MoO3. Both experimental results and density functional theory calculations suggest that the inclusion of Fe can effectively reduce the formation energy barrier while facilitating the desorption process of N-formylmorpholine, thereby optimizing the overall performance.

Pulsed Electrocatalysis Enabling High Overall Nitrogen Fixation Performance for Atomically Dispersed Fe on TiO2.

Atomically dispersed Fe was designed on TiO2 and explored as a Janus electrocatalyst for both nitrogen oxidation reaction (NOR) and nitrogen reduction reaction (NRR) in a two-electrode system. Pulsed electrochemical catalysis (PE) was firstly involved to inhibit the competitive hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). Excitingly, an unanticipated yield of 7055.81 µmol h-1 g-1 cat. and 12 868.33 µmol h-1 g-1 cat. were obtained for NOR and NRR at 3.5 V, respectively, 44.94 times and 7.8 times increase in FE than the conventional constant voltage electrocatalytic method. Experiments and density functional theory (DFT) calculations revealed that the single-atom Fe could stabilize the oxygen vacancy, lower the energy barrier for the vital rupture of N≡N, and result in enhanced N2 fixation performance. More importantly, PE could effectively enhance the N2 supply by reducing competitive O2 and H2 agglomeration, inhibit the electrocatalytic by-product formation for longstanding *OOH and *H intermediates, and promote the non-electrocatalytic process of N2 activation.