We use density functional theory calculations to study a group of 2D materials known as MXenes toward the electrochemical nitrogen reduction reaction (NRR) to ammonia. So far, all computational studies have only considered the NRR chemistry on unfunctionalized (bare) MXenes. In this study, we investigate a total of 65 bare and functionalized MXenes. We establish free energy diagrams for the NRR on the basal planes of 55 different M 2 XT x MXenes (M = Ti, V, Zr, Nb, Mo, Ta, W; X = C, N) to span a large variety of possible chemistries. Energy trends with respect to the metal as well as nonmetal constituent of the MXenes are established for both bare and functionalized MXenes. We determine the limiting potentials and find that either the formation of NH 3 from *NH 2 or the formation of *N 2 H is the potential limiting reaction step for bare and functionalized MXenes, respectively. We find several Mo-, W-, and V-based MXenes (Mo 2 C, Mo 2 N, W 2 N, W 2 NH 2 , and V 2 N) to have suitable theoretical overpotentials for the NRR. Importantly, calculated Pourbaix stability diagrams combined with selectivity analysis, however, reveal that all bare MXenes are not stable under relevant NRR operating conditions. The only functionalized MXene with the three minimum required properties (i) having a low theoretical overpotential, (ii) being stable under NRR conditions, and (iii) having selectivity toward NRR rather than the parasitic HER is W 2 CH 2 , which is a H-terminated MXene. Finally, on the basis of our findings, we explore other routes for improving the NRR chemistry by studying 10 additional MXenes with the chemical formula M 3 X 2 T x and MXenes with other functional groups (T x = S, F, Cl). This opens up a larger variety and tunability of MXenes to be considered for the NRR.

Hydrodeoxygenation (HDO) of m-cresol to produce toluene over carbon-supported Pt and Pt-WO x catalysts was studied. In stark contrast to Pt/C that exhibits only modest selectivity and low stability for this reaction, Pt-WO x /C was found to be unusually active and selective to toluene with greater than 94% selectivity to this product while exhibiting little to no deactivation under a wide range of reaction conditions. Reactivity studies in combination with density functional theory (DFT) calculations for the adsorption and reaction of m-cresol on structurally optimized WO x -decorated Pt(111) structures indicate that the HDO reaction on Pt-WO x /C proceeds via a direct hydrogenolysis of the C–O bond in m-cresol adsorbed on oxygen vacancy (or redox) sites on WO x species. The DFT results also indicate that Pt helps stabilize the WO x film while facilitating oxygen vacancy formation.

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