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<p>Calcium copper titanate (CCTO) is a novel functional material renowned for its exceptional dielectric properties and recent application as a photocatalyst. This study employs a green aqueous facile sol-gel technique to synthesize template-free, 3D-connected hierarchically porous monolithic CCTOs under two gelation and aging conditions (30&#xa0;°C and 40&#xa0;°C). Both samples exhibited identical thermal, crystalline, compositional, optical, and bandgap characteristics, with intrinsic direct and indirect band gaps of 1.99&#xa0;eV and 1.71&#xa0;eV, respectively. However, the porosity differed: the 30&#xa0;°C sample had a higher macropore volume, while the 40&#xa0;°C sample had a higher meso-/micropore volume, resulting in BET surface areas of 127&#xa0;m²/g and 53&#xa0;m²/g, respectively. Despite high calcination at 1100&#xa0;°C (&gt; 100&#xa0;nm particle size), which reduced surface areas to 0.4&#xa0;m²/g and 0.5&#xa0;m²/g, the pore structures remained. These one-step, template-free hierarchically porous CCTO materials show significant potential in catalysis, offering advantages such as efficient mass transport within macropores, high active surface area within meso-/micropores, reduced diffusional limitations, improved catalyst recovery due to their monolithic morphology, and visible region light absorbance for photocatalysis. The research shows the mesopore/surface area can be improved via lower-temperature calcination (e.g. 800&#xa0;°C; 40&#xa0;nm particle size) with extended duration, or alternative techniques like microwave calcination.</p>

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Facile synthesis of template-free 3D-connected hierarchically porous CaCu3Ti4O12 monolith by a green aqueous sol-gel method

  • 期刊论文

  • 发表日期：

    2025年3月18日

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  • Pascal Nbelayim,
  • Xuanming Lu,
  • Pierre Kalenga Mubiayi,
  • George Hasegawa,
  • Nosipho Moloto,
  • Kazuki Nakanishi

摘要

Calcium copper titanate (CCTO) is a novel functional material renowned for its exceptional dielectric properties and recent application as a photocatalyst. This study employs a green aqueous facile sol-gel technique to synthesize template-free, 3D-connected hierarchically porous monolithic CCTOs under two gelation and aging conditions (30 °C and 40 °C). Both samples exhibited identical thermal, crystalline, compositional, optical, and bandgap characteristics, with intrinsic direct and indirect band gaps of 1.99 eV and 1.71 eV, respectively. However, the porosity differed: the 30 °C sample had a higher macropore volume, while the 40 °C sample had a higher meso-/micropore volume, resulting in BET surface areas of 127 m²/g and 53 m²/g, respectively. Despite high calcination at 1100 °C (> 100 nm particle size), which reduced surface areas to 0.4 m²/g and 0.5 m²/g, the pore structures remained. These one-step, template-free hierarchically porous CCTO materials show significant potential in catalysis, offering advantages such as efficient mass transport within macropores, high active surface area within meso-/micropores, reduced diffusional limitations, improved catalyst recovery due to their monolithic morphology, and visible region light absorbance for photocatalysis. The research shows the mesopore/surface area can be improved via lower-temperature calcination (e.g. 800 °C; 40 nm particle size) with extended duration, or alternative techniques like microwave calcination.