Three-dimensional (3D) porous boron-doped diamond (BDD) film is an attractive electrode material but tough to synthesize. Herein, the 3D porous BDD films were constructed in a facile and template-free way. The BDD/non-diamond carbon (NDC) composite films were firstly fabricated by hot filament chemical vapor deposition (HFCVD) technique, and then the porous BDD films with 3D interconnected porous microstructure, different pore size and NDC-free diamond were achieved by selective removal of NDC. It is manifested that higher electrochemical response, large double layer capacitance (17.54 mF/cm²) in diamond electrodes, wide electrochemical window of 2.6 V and superior long-term stability were achieved for 3D porous BDD film. This derives from the synergistic effect of microstructure and phase composition of the porous films. 3D interconnected structure possesses prominent improvement of effective surface area and accessible porous channel, significantly enhancing the species adsorption and mass transfer. The 3D porous BDD films, composed of NDC-free diamond, exhibit excellent structural stability and corrosion resistance, which favor the enhancement of long-term stability and water splitting overpotential. The facile fabricating approach and excellent structure/electrochemical character demonstrate the appealing application in many electrochemical fields for 3D porous BDD films, such as energy storage and conversion, wastewater treatment and purification.

三维 (3D) 多孔掺硼金刚石 (BDD) 薄膜是一种有吸引力的电极材料，但难以合成。在此，3D 多孔 BDD 膜以一种简便且无模板的方式构建。BDD/非金刚石碳（NDC）复合薄膜首先采用热丝化学气相沉积（HFCVD）技术制备，然后通过选择性制备具有3D互连多孔微结构、不同孔径和不含NDC的金刚石的多孔BDD薄膜。去除 NDC。这表明较高的电化学响应、较大的双电层电容（17.54 mF/cm ²) 在金刚石电极中，3D 多孔 BDD 膜实现了 2.6 V 的宽电化学窗口和优异的长期稳定性。这源于多孔膜的微观结构和相组成的协同作用。3D互连结构显着提高了有效表面积和可接近的多孔通道，显着增强了物种吸附和传质。由无 NDC 金刚石组成的 3D 多孔 BDD 薄膜表现出优异的结构稳定性和耐腐蚀性，有利于提高长期稳定性和水分解过电位。简便的制造方法和优异的结构/电化学特性证明了 3D 多孔 BDD 薄膜在许多电化学领域的吸引力，例如能量存储和转换，