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The atomic and electronic structures of the BaTiO 3 (110) polar surface were systematically investigated by first-principles density functional theory (DFT) calculations with use of slab models. The relaxations and rumplings of five different (1 × 1) terminations were considered. According to the results of the charge redistribution, the polarity compensation conditions can be achieved in both stoichiometric and nonstoichiometric terminations, but their compensation mechanisms are obviously different. For the BaTiO and O 2 stoichiometric terminations, the intensive electronic structure changes with respect to the bulk crystal result in larger structural distortions and cleavage energies than the nonstoichiometric ones. For the TiO, Ba, and O nonstoichiometric terminations, whose electronic structures are qualitatively similar to that of the bulk crystal, their insulating characteristics are retained because no filling of surface states was found. Furthermore, the computation results of the surface grand potentials (SGPs), which were used to distinguish the relative stabilities of different terminations, clearly suggest the existence of four distinct stable (110) terminations, in which the BaTiO stoichiometric termination can only exist in a small region with O-poor condition.

Encouraged by the remarkable productivity improvements in the manufacturing sector, the construction industry has a long history of trying to garner the benefits of manufacturing technologies. Whereas industrialized construction methods, such as modular and manufactured buildings, have evolved over decades, core techniques used in prefabrication plants vary only slightly from those employed in traditional site-built construction. The objective of this research was to develop and implement a production system for the effective application of lean tools in building components prefabrication. To overcome the prevalent skepticism among middle management, the lean journey started with a pilot project involving one production line. Over a six-month period, lean tools such as 5S (sort, straighten, shine, standardize, and sustain), standardized work, takt time planning, variation management, and value stream mapping were implemented to a communication shelter production line. The implementation successfully won the support of the middle managers and established the foundation for expanding lean practices to other parts of the factory and applying relevant lean tools and techniques.

Herein, this study successfully fabricates porous g‐C3N4‐based nanocomposites by decorating sheet‐like nanostructured MnOx and subsequently coupling Au‐modified nanocrystalline TiO2. It is clearly demonstrated that the as‐prepared amount‐optimized nanocomposite exhibits exceptional visible‐light photocatalytic activities for CO2 conversion to CH4 and for H2 evolution, respectively by ≈28‐time (140 µmol g−1 h−1) and ≈31‐time (313 µmol g−1 h−1) enhancement compared to the widely accepted outstanding g‐C3N4 prepared with urea as the raw material, along with the calculated quantum efficiencies of ≈4.92% and 2.78% at 420 nm wavelength. It is confirmed mainly based on the steady‐state surface photovoltage spectra, transient‐state surface photovoltage responses, fluorescence spectra related to the produced •OH amount, and electrochemical reduction curves that the exceptional photoactivities are comprehensively attributed to the large surface area (85.5 m2 g−1) due to the porous structure, to the greatly enhanced charge separation and to the introduced catalytic functions to the carrier‐related redox reactions by decorating MnOx and coupling Au‐TiO2, respectively, to modulate holes and electrons. Moreover, it is suggested mainly based on the photocatalytic experiments of CO2 reduction with isotope 13CO2 and D2O that the produced •CO2 and •H as active radicals would be dominant to initiate the conversion of CO2 to CH4.

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We have successfully synthesized boron-doped g-C3N4 nanosheets (B-CN) and its nanocomposites with nanocrystalline anatase TiO2 (T/B-CN). The as-prepared T/B-CN nanocomposites with the proper amounts of boron and TiO2 exhibit rather high cocatalyst-free photoactivities for producing H2 from CH3OH solution (∼29× higher) and CH4 from CO2-containing water (∼16× higher) under visible-light irradiation, compared to those of bare g-C3N4. This is attributed to the greatly enhanced photogenerated charge separation after doping boron and subsequent coupling with TiO2, mainly based on the measurements of atmosphere-controlled steady-state surface photovoltage spectra, transient-state surface photovoltage responses, photoluminescence spectra, and fluorescence spectra related to the produced hydroxyl radical amount. It is suggested for the first time that the great charge separation enhancement results from the B-induced surface states near the valence band top to trap holes and the formed heterojunctions to transfer electrons from B-CN to TiO2. Moreover, the created surface states are also responsible for the visible-light extension from 450 nm of g-C3N4 to 500 nm of B-CN (T/B-CN) for solar fuel production. Interestingly, the obtained 6T/6B-CN exhibits much larger quantum efficiencies, which are 3.08% for hydrogen evolution and 1.68% for CH4 production at λ = 420 nm, respectively, with 5.1× and 7.6× enhancement as compared to CN, even superior to other works. This work will provide feasible routes to synthesize g-C3N4-based nanophotocatalysts for efficient solar fuel production.

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To elucidate the microscopic origin of the difference behaviors, first-principles calculations were performed to investigate the thermal and mechanical stabilities of LixFePO4 and LixMnPO4. The calculated free energies suggested that LiFePO4 and LiMnPO4 are thermal stable with respect to relevant oxides both in their pristine and fully delithiated states. According to the calculations, it can be identified that the shear deformations are more easier to occur with respect to the volume compressions in LixFePO4 and LixMnPO4, and this phenomenon is related to M-O(I) and M-O(II) bonds. Typically for MnPO4, Li(+) extraction from the host structures further weakens the Mn-O(I) bonds by about 33%, and it thus becomes very brittle. The shear anisotropy (AG) of MnPO4 is abnormally large and has already reached 19.05 %, which is about 6 times as large as that of FePO4. Therefore, shear deformations and dislocations occur easily in MnPO4. Moreover, as the Mn-O(I) bonds in MnPO4 are mainly spread within the {101} and {1̅01} crystal planes, the relevant slip systems thus allow the recombination of bonds at the interfaces, leading to the experimentally observed phase transformation. It can be concluded that mechanical reason will play an important role for the poor cycling performance of MnPO4.