Water is a significant by-product in the cobalt-based Fischer-Tropsch synthesis as the dissociation of CO on metallic cobalt must eventually lead to the formation of water. Hence, the removal of oxygen in the form of water, could potentially limit the intrinsic activity on a cobalt-based catalyst. In this study, potential mechanisms for the removal of strongly bound surface oxygen by hydrogenation to water on fcc Co(111) and Pt doped fcc Co(111) surfaces are investigated using density functional theory and micro-kinetic modelling to probe the effect that of platinum promotion. We show that the formation of water proceeds primarily via disproportionation of adsorbed OH, 2 OH ↔ H₂O + O, rather than the hydrogenation of surface hydoroxyl species, OH + H ↔ H₂O, on both surfaces. Doping cobalt with platinum increases the rate of oxygen removal in the form of water by four orders of magnitude, by reducing the barrier of the hydrogenation of surface oxygen, O + H ↔ OH, by 0.48 eV.

水是钴基费-托合成中的重要副产物，因为金属钴上的CO分解必须最终导致水的形成。因此，以水的形式除去氧气可能潜在地限制了对钴基催化剂的固有活性。在这项研究中，使用密度泛函理论和微动力学模型研究了通过在fcc Co（111）和Pt掺杂的fcc Co（111）表面上氢化成水来去除强结合的表面氧的潜在机理。白金促销。我们表明，水的形成主要是通过吸附的OH，2 OH↔ħ歧化前进₂ O + O，而不是表面hydoroxyl物种的氢化，OH + H↔ħ ₂在两个表面上均为O。通过将表面氧O + H OH的氢化势垒降低0.48 eV，用铂掺杂钴可以将水形式的氧去除速率提高四个数量级。