Solar cells and photocatalysts to yield hydrogen are two significant strategies for taking advantage of clean and sustainable solar energy, and their light manipulation and harvesting ability will play a dominant role in their conversion efficiencies. Butterflies demonstrate their brilliant colors due to their wonderful skills of light manipulation, originating intrinsically from their elaborate architectures. We review the inspiration of butterflies for solar cells and sunlight water-splitting catalysts, focusing on the nipple arrays in butterfly compound eyes, as well as ridge and hole arrays, and the photonic crystal structures in butterfly wing scales. After giving a brief introduction to the typical architectures, we reveal the physical principles lying behind antireflection of compound eyes and black scales and iridescence of wing scales, respective prototypes are extracted and highlighted for the design and fabrication of solar cells and sunlight water-splitting catalysts. We conclude by reviewing the prospects for the integration of these prototypes and the appropriate materials for solar energy, which is the product of an intimate conversation between humanity and nature, as well as close cooperation between scientists from diverse fields.

We report the investigation of a nano-scale antireflection structure in the black scales of the Troides aeacus butterfly wing, which can be viewed as a natural solar collector. The intelligence of light capturing hides itself in the intricate architectures aside from melanin effect. Reflection and transmission spectra of scales were obtained experimentally as well as with 3D FDTD (three dimensional finite difference time domain) method. Poynting vector maps which show the energy distribution of reflection and transmission in the micro geometric structure were portrayed as well. We demonstrated that the structure related antireflection behaviour is derived from the coupling effect of two main subunits of the hierarchical architecture, which are periodically aligned inverse-V type ridges and sub-wavelength nano-hole arrays.

Carbon-coated α-Fe2O3 hollow nanospindles and varied-phase Fe2O3@C (γ-Fe2O3@C, αγ-Fe2O3@C, and α-Fe2O3@C) nanobipyramids were prepared by controlling pyrolysis of MIL-88A nanobipyramids at different temperature and time in air or nitrogen, exhibiting advanced lithium storage capacities.

Porous (Co, Mn)(Co, Mn)2O4-based microspheres (CM-11-Ms) and core–shell microspheres (CM-11-CSMs) were firstly synthesized via controlled pyrolysis of CoMn-precursor microspheres at different temperatures under nitrogen, exhibiting advanced lithium storage capacities.

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Natural chloroplasts containing big amounts of chlorophylls (magnesium porphyrin, Mg-Chl) are employed both as template and porphyrin source to synthesize biomorphic CoNC/CoO x composite as electrocatalyst for the oxygen reduction reaction (ORR). Cobalt-substituted chlorophyll derivative (Co-Chl) in chloroplasts is first obtained by successively rinsing in hydrochloric acid and cobalt acetate solutions. After calcining in nitrogen to 800 °C, Co-Chl is transferred to CoNC; while other parts of chloroplasts adsorbed with Co ions are transferred to CoO x retaining the microarchitecture of chloroplasts. The abundant active CoNC sites are protected by circumjacent biocarbon and CoO x to avoid leakage and agglomeration, and at the same time can overcome the poor conductivity weakness of CoO x by directly transporting electrons to the carbonaceous skeleton. This unique synergistic effect, together with efficient bioarchitecture, leads to good electrocatalytical performance for the ORR. The onset and half-wave potentials are 0.89 and 0.82 V versus reversible hydrogen electrode, respectively, with better durability and methanol tolerance than that of commercial Pt/C. Different from the traditional concept of biomorphic materials which simply utilize bioarchitectures, this work provides a new example of coupling bioderivative components with bioarchitectures into one integrated system to achieve good comprehensive performance for electrocatalysts. Biomorphic Electrocatalysts www.advancedsciencenews.com

Preparing advanced electrocatalysts via solid-phase reactions encounters the challenge of low controllability for multiconstituent hybridization and microstructure modulation. Herein, a hydrothermal-mimicking solid-phase system is established to fabricate novel Fe 2 O 3 /Fe 5 C 2 /Fe−N−C composites consisting of Fe 2 O 3 /Fe 5 C 2 nanoparticles and Fe,N-doped carbon species with varying morphologies. The evolution mechanism featuring a competitive growth of different carbon sources in a closed hypoxic space is elucidated for a series of Fe 2 O 3 /Fe 5 C 2 /Fe− N−C composites. The size and dispersity of Fe 2 O 3 /Fe 5 C 2 nanoparticles, the graphitization degree of the carbonaceous matrix, and their diverse hybridization states lead to disparate electrocatalytic behaviors for the oxygen reduction reaction (ORR). Among them, microspherical Fe 2 O 3 /Fe 5 C 2 /Fe−N−C-3 exhibits an optimal ORR performance and the as-assembled zinc−air battery shows all-round superiority to the Pt/C counterpart. This work presents a mild solid-phase fabrication technique for obtaining a variety of nanocomposites with effective control over composition hybridization and microstructural modulation, which is significantly important for the design and optimization of advanced electrocatalysts.