On the basis of first‐principles calculations, the potential of applying 2D honeycomb‐kagome polymers made of heteroatom‐centered triangulene derivatives to photocatalyze water splitting is explored. The designed 2D polymers possess indirect bandgaps in the range of 1.80–2.84 eV and show pronounced light absorption in the ultraviolet and visible region of the solar spectrum. With suitable band edge alignment, the examined N‐ and B‐center polymers can generate sufficient photon‐excited electrons and holes to activate the hydrogen and oxygen evolution reactions, respectively. The combination of lattice‐inherent band features (flat bands) with chemical functionalization (potential shift due to heteroatoms) makes it possible to construct tandem cells with suppressed electron/hole recombination for effective overall water splitting. In addition, there is a potential difference between the half‐electrodes that can be utlized to power​ auxiliary components in self‐sufficient photocatalyzers.

On the basis of first-principles calculations, we report the design of three twodimensional (2D) binary honeycomb-kagome polymers composed of B-and N-centered heterotriangulenes with a periodically alternate arrangement as in hexagonal boron nitride. The 2D binary polymers with donor−acceptor characteristics are semiconductors with a direct band gap of 1.98−2.28 eV. The enhanced in-plane electron conjugation contributes to high charge carrier mobilities for both electrons and holes, about 6.70 and 0.24 × 10 3 cm 2 V −1 s −1 , respectively, for the 2D binary polymer with carbonyl bridges (2D CTPAB). With appropriate band edge alignment to match the water redox potentials and pronounced light adsorption for the ultraviolet and visible range of spectra, 2D CTPAB is predicted to be an effective photocatalyst/photoelectrocatalyst to promote overall water splitting.

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The development of effective electrode materials is essential to realizing high- performance lithium ion batteries (LIBs), which play an important role in powering modern society. By means of first-principles calculations, we have herein explored the potential of two-dimensional (2D) polymers made of carbonyl-bridged triphenylamine (CTPA) and carbonyl-bridged triphenylborane (CTPB) as electrode materials for LIBs. Our investigations demonstrate that the carbonyl groups of 2D CTPB and CTPA are rather active to accommodate Li. Both 2D CTPA and CTPB show the transition from semiconductor to metal after combining with Li. The migration of Li through the pore space of 2D CTPB and CTPA is facilitated with the diffusion barrier of 0.76 and 0.79 eV, respectively. 2D CTPB exhibits a high theoretical capacity of 760.86 mAh g-1 because it can accommodate Li at both the carbonyl sites and the surface sites of the skeleton, which is ascribed to the promotion of the electron-deficient B center. As a comparison, 2D CTPA can only combine with Li at the carbonyl sites and shows a capacity of 251.09 mAh g-1. With fast Li-diffusion ability, high capacity and low average operating voltage, 2D CTPA and CTPB are predicted to be promising non-metal anode materials for LIBs.