打擾各位前輩：
本人做了一個超薄Fe2P納米片修飾CdS納米棒，打算模擬計(jì)算純CdS納米棒以及Fe2P-CdS復(fù)合物的氫能。希望可以模擬的機(jī)構(gòu)聯(lián)系我報(bào)價，想合作的同學(xué)老師聯(lián)系我，報(bào)要求。
計(jì)算的內(nèi)容如下：
1、分別優(yōu)化CdS和Fe2P的晶格結(jié)構(gòu)，得到晶格常數(shù)（其中CdS與Fe2P的標(biāo)準(zhǔn)模型MS數(shù)據(jù)庫里有，則需要切晶面，優(yōu)化結(jié)構(gòu)）
2、構(gòu)建CdS(101)表面和CdS(101)/Fe2P(111)異質(zhì)結(jié)，并進(jìn)行結(jié)構(gòu)優(yōu)化
3、分別計(jì)算H原子在CdS(101)表面和CdS(101)/Fe2P(111)異質(zhì)結(jié)上的吸附自由能
計(jì)算的方法直接套用文獻(xiàn)：《Insight into iron group transition metal phosphides (Fe2P, Co2P, Ni2P) for improving photocatalytic hydrogen generation》
具體步驟如下：該方法模擬計(jì)算了氮化碳與磷化鐵，氮化碳與磷化鎳等復(fù)合物的氫吸附自由能.The spin-polarization first-principles calculations were performed using the Vienna ab initio Software Package (VASP) [3]. The projector augmented wave potential was used with a plane-wave cutoff energy of 400 eV. The exchange correlation energy was described by the generalized gradient approximation (GGA) within the Perdew-Burke-Ernzerhof (PBE) [4]. The model of TMPs deposition on S-CN was constructed by employing a slab model to mimic the surface and interface of TMPs/S-CN system. 2×2 S-CN and √3×√3 TMPs supercells were employed. The model contains ~100 atoms in total as shown in Figure S9. For geometry optimization and electronic structures calculations, the Brillouin-zone integration was performed using 3×3×1 and 8×8×1 Monkhorst-Pack mesh, respectively. To avoid the layer-layer interactions due to the use of periodic boundary conditions, a vacuum space was set to ~20 Å.The free energies of the intermediate H* adsorption were obtained by [5]
∆GH = ∆EH + ∆EZPE – T∆SH
where ∆EH denotes the adsorption energy of H atoms, which is calculated by ∆EH = EnH – E(n–1)H – 1/2EH2. ∆EZPE and ∆SH are the difference in zero-point energy and the entropy between atomic adsorption and hydrogen in the gas phase, respectively. The contribution of entropies and ZPE for ∆GH were obtained as previous works reported [5], in which finally expressed by ∆GH = ∆EH + 0.35. The charge transfer was calculated by subtracting the charge density of isolated TMPs slab and S-CN from the total charge density of the TMPs/S-CN systems.
結(jié)果與結(jié)構(gòu)如圖所示,
圖1 Top and side views of (a) Fe2P/S-CN, (b) Co2P/S-CN and (c) Ni2P/S-CN systems.
圖2(a) The free-energy diagram of the photocatalytic H2 generation on S-CN, Fe2P/S-CN, Co2P/S-CN and Ni2P/S-CN. (b) The charge density distributions of Ni2P/S-CN system. Blue and yellow colors show the charge losing and gaining, respectively (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article).


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