Correcting H2O2 Transport Losses Using Multi-Rotation-Rate RRDE Data and Determining the 2e/4e Oxygen-Reduction Pathway
The research group measured the oxygen reduction reaction of a carbon-supported, precious-metal-free catalyst using a rotating ring-disk electrode. The attachments contain O2/N2 disk and ring polarization curves at 400, 900, 1600, and 2500 rpm, with three independent catalyst films at each rotation rate; they also contain records of per-spectrum gain, reference-electrode offset, and uncompensated resistance, ferricyanide collection-efficiency calibrations, and H2O2 pulse transport-recovery calibrations under the same hydrodynamic conditions.
Convert the O2 and N2 curves to a comparable iR-corrected RHE scale, subtract the disk and ring backgrounds, and calculate the hydrogen peroxide selectivity and electron-transfer number using the measured collection efficiency and H2O2 transport recovery at each rotation rate. Summarize the mean/SD at the specified potentials, complete a multi-rotation-rate Koutecky–Levich analysis, and determine whether the observed rotation-rate differences arise from the reaction pathway or from disk-to-ring transport. The report must explain the limitations imposed on the conclusions by low-rotation-rate transport losses, ring response, and K-L assumptions.
Generate analysis.py, rrde_calibration_summary.csv, rrde_corrected_curves.csv, selectivity_summary.csv, kl_kinetics.csv, rrde_qc.csv, rrde_corrected_curves.png, peroxide_selectivity.png, kl_diagnostics.png, and rrde_orr_report.md under /app/output. The tables must retain spectrum_id, rotation_rpm, replicate, potential, and units, and the numerical values in the figures and report must be verifiable from the CSV files; do not read data from outside /app/input, and do not hard-code reference results.
Deliverable Files
This section defines only the submission format and does not prescribe the analysis method or expected results. All files listed below are required and must be written directly to /app/output/. All CSV files must be UTF-8 text with headers; numeric fields must contain numeric values only, with units defined by the field names or the tables below. CSV column order and row order are not specified. Additional columns are permitted, but they must not replace the required fields listed below; each row is identified by the specified stable key.
/app/output/analysis.py
A UTF-8 text script that reproduces the results.
/app/output/rrde_calibration_summary.csv
Each row represents a calibration summary for one rotation rate; the stable key is rotation_rpm.
| Field | Type | Unit |
|---|---|---|
rotation_rpm |
integer | rpm |
n_collection_replicates |
integer | count |
collection_efficiency_mean |
number | dimensionless |
collection_efficiency_sd |
number | dimensionless |
n_peroxide_replicates |
integer | count |
peroxide_transit_recovery_mean |
number | dimensionless |
peroxide_transit_recovery_sd |
number | dimensionless |
/app/output/rrde_corrected_curves.csv
Each row represents one sampled point on an O2 curve; the stable key is the combination of spectrum_id and point_index.
| Field | Type | Unit |
|---|---|---|
spectrum_id |
string | — |
rotation_rpm |
integer | rpm |
replicate |
integer | — |
point_index |
integer | — |
potential_RHE_iR_corrected_V |
number | V vs RHE |
disk_current_background_corrected_mA |
number | mA |
disk_current_density_mA_cm2 |
number | mA/cm² |
ring_current_background_corrected_mA |
number | mA |
ring_current_transit_corrected_mA |
number | mA |
collection_efficiency |
number | dimensionless |
peroxide_transit_recovery |
number | dimensionless |
H2O2_percent |
number | % |
H2O2_percent_without_transit_correction |
number | % |
electron_transfer_number |
number | dimensionless |
/app/output/selectivity_summary.csv
Each row represents a replicate statistical summary for one combination of rotation rate and target potential; the stable key is the combination of rotation_rpm and potential_RHE_V.
| Field | Type | Unit |
|---|---|---|
rotation_rpm |
integer | rpm |
potential_RHE_V |
number | V vs RHE |
n_replicates |
integer | count |
H2O2_percent_mean |
number | % |
H2O2_percent_sd |
number | % |
H2O2_without_transit_correction_mean |
number | % |
H2O2_without_transit_correction_sd |
number | % |
electron_transfer_number_mean |
number | dimensionless |
electron_transfer_number_sd |
number | dimensionless |
disk_current_density_mean_mA_cm2 |
number | mA/cm² |
disk_current_density_sd_mA_cm2 |
number | mA/cm² |
/app/output/kl_kinetics.csv
Each row represents a summary of the kinetics and electron-transfer number at one target potential; the stable key is potential_RHE_V.
| Field | Type | Unit |
|---|---|---|
potential_RHE_V |
number | V vs RHE |
n_replicate_fits |
integer | count |
kinetic_current_density_mean_mA_cm2 |
number | mA/cm² |
kinetic_current_density_sd_mA_cm2 |
number | mA/cm² |
KL_electron_transfer_number_mean |
number | dimensionless |
KL_electron_transfer_number_sd |
number | dimensionless |
RRDE_electron_transfer_number_mean |
number | dimensionless |
RRDE_electron_transfer_number_sd |
number | dimensionless |
KL_r_squared_mean |
number | dimensionless |
KL_r_squared_minimum |
number | dimensionless |
/app/output/rrde_qc.csv
A single-row global summary table with no row key.
| Field | Type | Unit |
|---|---|---|
n_raw_spectra |
integer | count |
n_corrected_O2_curves |
integer | count |
n_points_per_curve |
integer | count |
collection_efficiency_min |
number | dimensionless |
collection_efficiency_max |
number | dimensionless |
peroxide_transit_recovery_min |
number | dimensionless |
peroxide_transit_recovery_max |
number | dimensionless |
maximum_corrected_H2O2_rotation_spread_percent |
number | percentage points |
maximum_uncorrected_H2O2_rotation_spread_percent |
number | percentage points |
minimum_KL_r_squared |
number | dimensionless |
maximum_KL_RRDE_n_disagreement |
number | dimensionless |
collection_calibration_status |
string | — |
background_ir_status |
string | — |
peroxide_transit_status |
string | — |
kinetic_status |
string | — |
pathway_status |
string | — |
overall_status |
string | — |
failure_reasons |
string | — |
Figures and Report
/app/output/rrde_corrected_curves.png: A PNG image showing the corrected disk and ring curves./app/output/peroxide_selectivity.png: A PNG image showing hydrogen peroxide selectivity and the result categories before and after correction./app/output/kl_diagnostics.png: A PNG image showing the K-L kinetic cross-check./app/output/rrde_orr_report.md: A UTF-8 Markdown report covering calibration and background treatment, hydrogen peroxide selectivity, the kinetic cross-check, QC, and limitations; its conclusions and numerical values must be supported by the submitted CSV files.