Molecular self-assembly is a promising approach to the preparation of nanostructures. DNA, in particular, shows great potential to be a superb molecular system. Synthetic DNA molecules have been programmed to assemble into a wide range of nanostructures. It is generally believed that rigidities of DNA nanomotifs (tiles) are essential for programmable self-assembly of well defined nanostructures. Recently, we have shown that adequate conformational flexibility could be exploited for assembling 3D objects, including tetrahedra, dodecahedra, and buckyballs, out of DNA three-point star motifs. In the current study, we have integrated tensegrity principle into this concept to assemble well defined, complex nanostructures in both 2D and 3D. A symmetric five-pointstar motif (tile) has been designed to assemble into icosahedra or large nanocages depending on the concentration and flexibility of the DNA tiles. In both cases, the DNA tiles exhibit significant flexibilities and undergo substantial conformational changes, either symmetrically bending out of the plane or asymmetrically bending in the plane. In contrast to the complicated natures of the assembled structures, the approach presented here is simple and only requires three different component DNA strands. These results demonstrate that conformational flexibility could be explored to generate complex DNA nanostructures. The basic concept might be further extended to other biomacromolecular systems, such as RNA and proteins.icosahedron ͉ three-dimensional ͉ polyhedron ͉ cryo-EM ͉ molecular cages M olecular self-assembly provides a bottom-up approach to the preparation of nanostructures (1-3). DNA, in particular, shows great potential to be a superb molecular system (4). In the last 20 years, DNA has been explored as building blocks for nanoconstructions, including preparation of periodic and aperiodic 2D nanopatterns (5-8) and 3D polyhedra (9-14). Most of the branched DNA structures are intrinsically flexible and are not suitable building blocks for construction of well defined geometric structures. How to overcome the conformational flexibility of branched DNA structures is a major challenge in structural DNA nanotechnology. In the last decade, a series of rigid structural motifs have been successfully engineered that lead to the rapid evolution of structural DNA nanotechnology (4). However, with more experience and knowledge, it is possible to controllably introduce the conformational flexibility to prepare complex DNA nanostructures (15). In our recent study of 3D self-assembly of DNA three-point-star tiles (16), we found that DNA tetrahedra could be readily assembled, and the tetrahedra are well behaved during sample characterizations. In contrast, DNA dodecahedra and buckyballs have significantly lower assembly yields and are prone to deformation. This phenomenon can be explained by the geometrical differences of these structures. Tetrahedra consist of triangular faces, but others do not. According to tensegrity principle, triangular faces will lead to rigid s...

Solar‐driven photocatalytic CO2 reduction is regarded as a promising way to simultaneously mitigate the energy crisis and CO2 pollution. However, achieving high efficiency of photocatalytic CO2 reduction, especially without the assistance of sacrifice reagents or extra alkaline additives, remains a critical issue. Herein, a photocatalyst of 3D ordered macroporous N‐doped carbon (NC) supported CdS quantum dots (3DOM CdSQD/NC) is successfully fabricated toward photocatalytic CO2 reduction via an in situ transformation strategy. Additionally, an amines oxidation reaction is introduced to replace the H2O oxidation process to further boost the photocatalytic CO2 reduction efficiency. Impressively, 3DOM CdSQD/NC exhibits superior activity and selectivity in photocatalytic CO2 reduction coupled with amines oxidation, affording a CO production rate as high as 5210 µmol g−1 h−1 in the absence of any sacrificial agents and alkaline additives. Moreover, 3DOM CdSQD/NC achieves an apparent quantum efficiency of 2.9% at 450 nm. Mechanism studies indicate that the 3D ordered macropores in the NC matrix are beneficial to the transfer of photogenerated carriers. Furthermore, the highly dispersed CdS QDs on the NC skeleton are able to significantly promote the adsorption of both CO2 and amine molecules and depress the CO2 activation energy barriers by stabilizing the *COOH intermediate, directly contributing to the high activity.

Rationally tailoring the coordination environments of metal single atoms (SAs) is an effective approach to promote their catalytic performances, which, however, remains as a challenge to date. Here, we report a novel misplaced deposition strategy for the fabrication of differently coordinated dual-metal hetero-SAs. Systematic characterization results imply that the as-synthesized dual-metal hetero-SAs (exemplified by Cu and Co) are affixed to a hierarchical carbon support via Cu–C4 and Co–N4 coordination bonds. Density functional theory studies reveal that the strong synergistic interactions between the asymmetrically deployed CuC4 and CoN4 sites lead to remarkably polarized charge distributions, i.e., electron accumulation and deficiency around CuC4 and CoN4 sites, respectively. The obtained CuC4/CoN4@HC catalyst exhibits significantly enhanced capability in substrate adsorption and O2 activation, achieving superior catalytic performances in the oxidative esterification of aromatic aldehydes in comparison with the Cu- and Co-based SA counterparts.

To utilize intermittent renewable energy as well as achieve the goals of peak carbon dioxide emissions and carbon neutrality, various electrocatalytic devices have been developed. However, the electrocatalytic reactions, e.g., hydrogen evolution reaction/ oxygen evolution reaction in overall water splitting, polysulfide conversion in lithium− sulfur batteries, formation/decomposition of lithium peroxide in lithium−oxygen batteries, and nitrate reduction reaction to degrade sewage, suffer from sluggish kinetics caused by multielectron transfer processes. Owing to the merits of accelerated charge transport, optimized adsorption/desorption of intermediates, raised conductivity, regulation of the reaction microenvironment, as well as ease to combine with geometric characteristics, the built-in electric field (BIEF) is expected to overcome the above problems. Here, we give a Review about the very recent progress of BIEF for efficient energy electrocatalysis. First, the construction strategies and the characterization methods (qualitative and quantitative analysis) of BIEF are summarized. Then, the up-to-date overviews of BIEF engineering in electrocatalysis, with attention on the electron structure optimization and reaction microenvironment modulation, are analyzed and discussed in detail. In the end, the challenges and perspectives of BIEF engineering are proposed. This Review gives a deep understanding on the design of electrocatalysts with BIEF for nextgeneration energy storage and electrocatalytic devices.

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