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This text describes the data presented in the paper: "Evaluation of Porous Carbon Felt as an Aerobic Biocathode Support in terms of Hydrogen Peroxide Formation"

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Introductory information
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Files included in the data deposit: 

Figure 3 raw (.xls and .csv) - Raw PWE and SSE current data for Figure 3 (treated and untreated carbon felt)
Figure 3 processed (.xls and .csv) - PWE and SSE current data for Figure 3 (treated and untreated carbon felt) after applying the Savitky-Golay filter. Data were averaged across two runs and then normalised to electrode area.  
Figure 5A (.xls and .csv) - Raw CA data for two bioelectrochemical half-cells with untreated carbon felt poised at -0.1 and -0.2 V
Figure 5B (.xls and .csv) - Raw CV data for two bioelectrochemical half-cells with untreated carbon felt poised at -0.1 and -0.2 V 
Table 1 (.xls and .csv) - Summary table of poised potentials for treated and untreated carbon felt

Key words used to describe the data:
4-electrode half-cell
Bioelectrochemical half-cell
Primary Working Electrode (PWE)
Secondary Sensing Electrode (SSE)
Chronoamperometry (CA)
Cyclic voltammatry (CV)
Working Electrode (WE)
Reference Electrode (RE)
Counter Electrode (CE)

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Methodological information
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What the data is, how and why it was collected or created, and how it was processed:

Two different carbon felt supports, one treated with nitric acid, the other untreated, were characterized electrochemically through a series of chronoamperometry (CA) experiments using a 4-electrode half-cell, in order to determine the potential at which peroxide is initially formed on porous carbon felt. The measurements were recorded using a potentiostat (Autolab PGSTAT302, Metrohm, UK). Raw PWE and SSE data were filtered using a Savitky-Golay filter, and average data with error bars for two experimental runs normalised to the electrode area were plotted. The SSE data were then modelled mathematically from the PWE data. Additionally, two bioelectrochemical half-cells poised at -0.2 and -0.1 V were setup in order to study biocathode formation. Raw CA and CV are provided for these two half-cells. Raw CA data for two bioelectrochemical half-cells were recorded using a 4-channel potentiostat (Whistonbrook Technologies, UK). Raw CV data for two bioelectrochemical half-cells were recorded using a potentiostat (Autolab PGSTAT302, Metrohm, UK).

**4-electrode half-cell data**

Raw PWE and SSE data were output from a potentiostat (Autolab PGSTAT302, Metrohm, UK) for untreated and treated carbon felt as the PWE. A Savitky-Golay filter was then applied to the raw PWE and SSE data to improve the S/N ratio. The post-filtered PWE data (See "Figure 3 processed.csv" -> sheets PWE1 and PWE2) was then treated in the following way; 
1. Time adjusted to zero by subtraction of first 918s, the start of electrode polarization.
2. Average current in amps of both runs taken
3. Average current in amps was converted to micro amps per square cm using an electrode area of 24 cm2
4. Average current in amps per square cm was plotted with error bars (difference/2). The error bars were plotted every 500s

The SSE data was processed in the following way (See "Figure 3 processed.csv" -> sheets SSE1, SSE2 and SSE3); 
1. Average current in amps of both runs taken 
2. Time adjusted to zero by subtraction of the first 900s 
3. Average current in amps was converted to micro amps per square cm using an electrode area of 2 cm2
4. Average current in amps per square cm was plotted with error bars (difference/2) plotted every 500s

The SSE current was also modelled from the PWE current (See "Figure 3 processed.csv" -> sheets MOD1 and MOD2); 
1. The PWE current was x by -1 to make all reduction currrent values positive.
2. To remove the capacitive current from the PWE current (first 2 mins), the current was fit to a first order exponential decay from row 15 onwards of sheet MOD1 using the Excel solver pluggin, and the solution extrapolated back to t=0.
3. r (k1 in the data sheet) was calculated from the PWE current using equation 6.
4. k (k2 in the data sheet) was taken from the literature. r and k were then fed into equation 10 to derive [H2O2] over time.

**Bioelectrchemical half-cell data**

Raw CA data were collected on a 4-channel potentiostat (Whistonbrook Technologies, UK) every 900s for ~30 days for two bioelectrochemical half-cells poised at -0.1 and -0.2 V vs Ag/AgCl. CA data were processed by normalising to the electrode area (dividing by 12.16 cm2 and converting to microamps), and instantaneous current spikes due to discharge of capacitive current were removed by taking the median of every 10 current values (2.5 hrs). These current spikes result from disconnecting/re-connecting the potentiostat. The CA data was then plotted (See "Figure 5A.csv"). CV data were recorded for the two bioelectrochemical half-cells at 0 and 7 days of operation. The CV were recorded using a potentiostat (Autolab PGSTAT302, Metrohm, UK) at a scan rate of 5 mV/s between -0.2 and +0.5 V (See "Figure 5B.csv"). Raw CV data were processed by normalising to electrode area (dividing by 12.16 cm2 and converting to microamps).   

Instruments, hardware and software used:
1. A 4-channel potentiostat (Whistonbrook Technologies, UK) was used to poise the WE of the bioelectrochemical half-cells and collect current data.
2. An Autolab PGSTAT302 potentiostat (Metrohm, UK) was used to simultaneously poise the WE potential and record the current for the SSE and PWE of the 4-electrode half-cell, and to record CV for the bioelectrochemical half-cells. NOVA software provided with the Autolab PGSTAT302 potentiostat was used to filter raw PWE and SSE current data. 
3. Microsoft Excel was used for all data processing, unless indicated otherwise. 

Date(s) of data collection: 
CA and CV data collected in 2013

Geographic coverage of data:
Data is for lab-based electrochemical systems which were operated in lab C318, Merz court (CEAM), Newcastle University.

Data validation (how was the data checked, proofed and cleaned):
Raw currents were obtained directly from potentiostat measurements. Potentiostats were fully-functional and calibrated prior to use. CA data from the 4-electrode electrochemical half cell were cleaned by applying a Savitky-Golay filter (using Metrohm Autolab NOVA software) to improve the S/N ratio. CA data from the bioelectrochemical half-cell were cleaned by taking the median of 10 data points to remove capacitive current spikes.     

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Data-specific information
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Definitions of names, labels, acronyms or specialist terminology uses for variables, records and their values: 

4-electrode half-cell - A 4-electrode electrochemical cell comprising two WEs, one CE and one RE.
Bioelectrochemical half-cell - A 3-electrode electrochemical cell comprising one WE, one CE and one RE. Used to grow electroactive biofilms.
Chronoamperometry (CA) - An electrochemical method in which the WE potential is fixed and the current measured with time. 
Cyclic voltammatry (CV) - An electrochemical method in which the WE potential is scanned at a fixed rate in both a positive and negative direction whilst measuring the current.
Working electrode (WE) - The electrode on which the reaction being studied occurs.
Counter electrode (CE) - The electrode which balances the current at the WE.
Reference electrode (RE) - The electrode against which the potential at the WE is measured.
Primary working electrode (PWE) - The first WE of the 4-electrode half-cell.
Secondary sensing electrode (SSE) - The second WE of the 4-electrode half-cell.

Explanation of weighting and grossing variables:
Raw currents are normalised to the WE area using the WE geometric area.  

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Contact
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Please contact rdm@ncl.ac.uk for further information