title: Cubic phase templating of mesoporous platinum – synthesis, characterisation &amp; electrocatalytic properties
Creators: name: Alshammari, Afnan Qabil
Publisher: name: University of Reading
Year: 2025

description: The synthesis and application of mesoporous platinum materials with novel 3D cubic 
morphology and large pore spacing by utilising two amphiphilic molecules Brij® 58 and F127 
as structure-directing agents was explored. Brij® 58 and F127, when mixed with water or 
hexacholorplatinic acid (HCPA), were found to form stable mesophases such as the face
centred cubic (FCC), body centred cubic (BCC), hexagonal (HI
), and lamellar (L∝), according to 
small angle x-ray scattering (SAXS) and cross polarising light microscopy (CPLM) data. This 
versatility made these systems ideal for mesoporous platinum synthesis. Interestingly, 
mesoporous platinum nanoparticles, ranging from 23 to 57 nm, were fabricated through a 
polyol synthesis-like mechanism at 80 °C utilising Brij® 58/HCPA at concentrations ranging 
from 30 to 60 wt% with no additional reducing agent. Mesoporous platinum electrodes (MPEs) 
were created using FCC (40 wt% of Brij® 58 ) and BCC templates (30 wt% of Brij® 58 and 50 
wt% of F127).
The FCC template from Brij® 58/HCPA was employed to create MPEs at various potentials. The
electrodes exhibited interesting surface features and an internal 3D cubic morphology most 
likely to be a diamond structure with pore diameters varying from 3.0 to 3.5 nm and lattice 
parameters ranging from 6.3 to 7.1 nm. They also demonstrated high electrochemically active 
surface areas (ECSA) with values up to ~27.6 m2 g
−1 and improved catalytic activity towards 
ethanol in acidic media. They illustrated high JF/JB ratios reaching a maximum of 1.19 and low 
onset potentials (Eonset) reaching a minimum of 0.35 V. Electrochemical impedance 
spectroscopy (EIS) emphasised small charge transfer resistance (Rct) and large double layer 
capacitance (Cdl) values for the MPEs. All films also demonstrated good long-term stability.
The BCC template of Brij® 58/HCPA was utilised to fabricate the MPEs at different potentials. 
The electrodes revealed exciting surface morphology and an internal 3D cubic morphology 
most likely to be a primitive structure with pore diameters ranging from 3.0 to 3.5 nm, and 
lattice parameters between 6.4 and 6.8 nm. Films revealed high ECSA reaching up to a 
maximum of ~ 31.2 m2 g
-1
for thin films and all films exhibited excellent catalytic activity 
towards ethanol oxidation. They demonstrated high JF/JB ratios reaching a maximum of 1.38
and low Eonset values reaching a minimum of 0.33 V. All films also exhibited excellent long-term 
stability.
The BCC template of F127/HCPA was used for electrodeposition of MPEs at various potentials. 
These MPEs revealed an internal 3D cubic morphology most likely to be a primitive structure
with large pore diameters of between 7.8 and 8.2 nm and lattice parameters from 16.4 to 
17.4 nm. Electrodes presented high ECSA ranging up to ~ 24.5 m2 g
-1 and superior catalytic 
activity for ethanol oxidation as recognised by high JF/JB ratios increasing to a maximum of 
1.05 and low Eonset values with a minimum of 0.37 V. EIS analysis highlighted good efficiency 
for ethanol oxidation, represented by low values of Rct and large Cdl values. The electrodes 
also displayed good long-term stability.
All MPEs in this study demonstrated, high ECSA and excellent catalytic activity for ethanol 
oxidation as evidenced by high JF/JB ratios, low Eonset values and enhanced stability. This 
behaviour, coupled with the interesting external surface morphology and internal cubic 
mesoporosity, suggests the potential for further applications (batteries, capacitors and other 
types of electrocatalysis) of these materials.