This paper presents a family of mesoporous non-precious metal (NPM) catalysts for the oxygen reduction reaction (ORR) in acidic media, including cobalt-nitrogen-doped carbon (C-N-Co) and iron-nitrogen-doped carbon (C-N-Fe). These catalysts were synthesized using vitamin B12 (VB12) and the polyaniline-Fe (PANI-Fe) complex, with silica nanoparticles, ordered mesoporous silica SBA-15, and montmorillonite as templates to achieve mesoporous structures. The most active catalyst, VB12/Silica colloid, exhibited a high ORR activity (half-wave potential of 0.79 V), high selectivity (electron transfer number > 3.95), and excellent electrochemical stability (only 9 mV negative shift after 10,000 potential cycles). The performance is attributed to the well-defined mesoporous structures, high Brunauer-Emmett-Teller (BET) surface area (up to 572 m²/g), and homogeneous distribution of abundant metal-Nx active sites. The study addresses the challenge of developing low-cost, high-performance ORR catalysts for proton-exchange-membrane (PEM) fuel cells, which rely on platinum-based catalysts due to the slow kinetics of the cathodic ORR. The NPM catalysts offer a promising alternative due to their unique electronic properties and structural features. The synthesis involves template synthesis using silica colloid, SBA-15, and montmorillonite to control the mesoporous structures. The resulting catalysts show high activity, selectivity, and durability, with the VB12/Silica colloid catalyst demonstrating the best performance. The electrochemical properties of the catalysts were evaluated using rotating ring-disk electrode (RRDE) techniques in sulfuric acid. The VB12/Silica colloid catalyst exhibited a high ORR activity, with a half-wave potential comparable to that of Pt/C catalysts. The catalyst also showed a high electron transfer number and low hydrogen peroxide yield, indicating a four-electron transfer process. The durability of the catalyst was tested by cycling between 0.6 and 1.0 V, with the VB12/Silica colloid catalyst showing minimal degradation after 10,000 cycles. The study also prepared mesoporous C-N-Fe catalysts using a polyaniline-Fe complex and silica colloids as templates. The C-N-Fe catalysts exhibited excellent ORR performance, with a high electron transfer number and low hydrogen peroxide yield. The results demonstrate the potential of mesoporous NPM catalysts for applications requiring high surface area and efficient mass transport, such as supercapacitors, batteries, and heterogeneous catalysis. The concept of mesoporous structure control is promising forThis paper presents a family of mesoporous non-precious metal (NPM) catalysts for the oxygen reduction reaction (ORR) in acidic media, including cobalt-nitrogen-doped carbon (C-N-Co) and iron-nitrogen-doped carbon (C-N-Fe). These catalysts were synthesized using vitamin B12 (VB12) and the polyaniline-Fe (PANI-Fe) complex, with silica nanoparticles, ordered mesoporous silica SBA-15, and montmorillonite as templates to achieve mesoporous structures. The most active catalyst, VB12/Silica colloid, exhibited a high ORR activity (half-wave potential of 0.79 V), high selectivity (electron transfer number > 3.95), and excellent electrochemical stability (only 9 mV negative shift after 10,000 potential cycles). The performance is attributed to the well-defined mesoporous structures, high Brunauer-Emmett-Teller (BET) surface area (up to 572 m²/g), and homogeneous distribution of abundant metal-Nx active sites. The study addresses the challenge of developing low-cost, high-performance ORR catalysts for proton-exchange-membrane (PEM) fuel cells, which rely on platinum-based catalysts due to the slow kinetics of the cathodic ORR. The NPM catalysts offer a promising alternative due to their unique electronic properties and structural features. The synthesis involves template synthesis using silica colloid, SBA-15, and montmorillonite to control the mesoporous structures. The resulting catalysts show high activity, selectivity, and durability, with the VB12/Silica colloid catalyst demonstrating the best performance. The electrochemical properties of the catalysts were evaluated using rotating ring-disk electrode (RRDE) techniques in sulfuric acid. The VB12/Silica colloid catalyst exhibited a high ORR activity, with a half-wave potential comparable to that of Pt/C catalysts. The catalyst also showed a high electron transfer number and low hydrogen peroxide yield, indicating a four-electron transfer process. The durability of the catalyst was tested by cycling between 0.6 and 1.0 V, with the VB12/Silica colloid catalyst showing minimal degradation after 10,000 cycles. The study also prepared mesoporous C-N-Fe catalysts using a polyaniline-Fe complex and silica colloids as templates. The C-N-Fe catalysts exhibited excellent ORR performance, with a high electron transfer number and low hydrogen peroxide yield. The results demonstrate the potential of mesoporous NPM catalysts for applications requiring high surface area and efficient mass transport, such as supercapacitors, batteries, and heterogeneous catalysis. The concept of mesoporous structure control is promising for