Earth-abundant electrocatalysts for stable hydrogen generation in acidic conditions at low overpotential are highly desirable and yet extremely challenging due to the corrosive degradation of the catalysts at low pH (≤ 2). Here, we demonstrate gas-phase, thermally-driven selective oxidative tuning of structure and morphology of bulk Ti₃AlC₂ (MAX phase) to yield (a) randomly oriented polycrystalline Ti_0.2Al_1.8C₄O₅ nanowires (TACO NW) or (b) oriented single crystalline Ti_0.2Al_1.7C₅O_5.3 nanorods (TACO NR). The polycrystalline TACO NW exhibits high electrochemical surface area (0.11 cm²) and low overpotential (248 mV) for hydrogen evolution reaction (HER) compared to TACO NR, in acidic conditions, highlighting an important, structure-property correlation. The mechanism of nanostructuring and its subsequent electrocatalytic pathway is presented. Consequently, the dimensionally confined TACO NW provides high kinetic facility (Tafel slope = 121 mV/dec) and low charge-transfer resistance (70 Ω), resulting in stable HER with high Faradic efficiency (98 %) and turnover frequency (1080 h⁻¹) at mass-activity (71,420 mA/g) that is significantly superior compared to several other similar systems.

由于在低pH（≤2）下催化剂的腐蚀降解，在酸性条件下以低超电势稳定地产生氢气的富含地球的电催化剂是非常需要的，但是却极具挑战性。在这里，我们展示了气相，热驱动的选择性氧化调节块状Ti ₃ AlC ₂（MAX相）的结构和形态，以产生（a）随机取向的多晶Ti _0.2 Al _1.8 C ₄ O ₅纳米线（TACO NW）或（b）取向单晶Ti _0.2 Al _1.7 C ₅ O _5.3纳米棒（TACO NR）。与TACO NR相比，在酸性条件下，多晶TACO NW的析氢反应（HER）具有较高的电化学表面积（0.11 cm ²）和较低的超电势（248 mV），突出了重要的结构性质相关性。介绍了纳米结构的机理及其随后的电催化途径。因此，在尺寸限制TACO NW提供高动能设施（塔菲尔斜率= 121毫伏/ DEC）和低电荷转移电阻（70Ω），导致稳定HER高法拉第效率（98％）和转换频率（1080ħ ^{- 1}）的质量活度（71,420 mA / g）显着优于其他几种类似系统。