Entropic Interface Group, Engineering Product Development, Singapore University of Technology and Design, 8 Somapah Road, 487372 Singapore, Singapore.
Phys Chem Chem Phys. 2018 Jul 11;20(27):18828-18836. doi: 10.1039/c8cp02535e.
By using first-principles approach, the interaction of CO2 with (001) surfaces of six cubic ABO3 perovskites (A = Ba, Sr and B = Ti, Zr, Hf) is studied in detail. We show that CO2 adsorption results in the formation of highly stable CO3-like complexes with similar geometries for all investigated compounds. This reaction leads to the suppression of the surfaces states, opening the band gaps of the slab systems up to the corresponding bulk energy limits. For most AO-terminated ABO3(001) perovskite surfaces, a CO2 coverage of 0.25 was found to be sufficient to fully suppress the surface states, whereas the same effect can only be achieved at 0.50 CO2 coverage for the BO2-terminated surfaces. The largest band gap modulation among the AO-terminated surfaces was found for SrHfO3(001) and BaHfO3(001), whereas the most profound effect among the BO2-terminated surfaces was identified for SrTiO3(001) and BaTiO3(001). Based on these results and considering practical difficulties associated with measuring conductivity of highly resistive materials, TiO2-terminated SrTiO3(001) and BaTiO3(001) were identified as the most prospective candidates for chemiresistive CO2 sensing applications.
采用第一性原理方法，详细研究了 CO2 与六种立方 AB03 钙钛矿（A = Ba、Sr 和 B = Ti、Zr、Hf）（001）表面的相互作用。我们表明，CO2 吸附导致形成具有相似几何形状的高度稳定的 CO3 类似物，对于所有研究的化合物都是如此。该反应导致表面态被抑制，从而将薄片系统的能带隙拓宽至相应的体能极限。对于大多数 AO 终止的 ABO3（001）钙钛矿表面，发现 CO2 覆盖率为 0.25 足以完全抑制表面态，而对于 BO2 终止的表面，相同的效果只能在 CO2 覆盖率为 0.50 时实现。在 AO 终止的表面中，发现 SrHfO3（001）和 BaHfO3（001）的能带隙调制最大，而在 BO2 终止的表面中，SrTiO3（001）和 BaTiO3（001）的影响最为显著。基于这些结果，并考虑到测量高阻材料电导率的实际困难，确定 TiO2 终止的 SrTiO3（001）和 BaTiO3（001）是用于化学电阻式 CO2 传感应用的最有前途的候选材料。
