Hi all

I came across this description of SOFNOCAT on a manufacture's technical data sheet that was in our lab.

"SOFNOCAT technology combines promoted platinum, palladium and tin oxide, with unique support chemistry, to produce a highly active and effective oxidation catalyst"

The data sheet also made mention of the different grades of SOFNOCAT (423 & 514), the relevance of this being that the 514 could be used to convert CO to CO2 and to also scrub H2, this would appear to have implications in regenerating the catalyst with H2.


Jason

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-----Original Message-----
From: Stable Isotope Geochemistry [mailto:[log in to unmask]] On Behalf Of Sergey Assonov
Sent: Friday, 17 June 2005 1:37 AM
To: [log in to unmask]
Subject: Re: [ISOGEOCHEM] CO catalyst

Pier and others,

SOFNOCAT catalytically oxidises CO - oxygen required!
 From our experience and as far as I remember from the SOFNOCAT
description, it is poisoned by SO2 and other sulphur-bearing gases. I am
not sure whether one can re-activate it.
Sergey



Paul Eby wrote:

> As I understand the catalyst, it requires oxygen in the gas stream to
> work.
> We are stripping CO out of air samples, so the oxygen is supplied in that
> manner.
>
> I'm wondering if reducing the catalyst under H2 might not improve things.
> Perhaps I'll just have to try it, but was hoping someone had beaten me to
> it....
>
> Paul
>
>
> At 08:11 AM 16/06/2005, you wrote:
>
>> Dear Paul and others,
>>
>> I looked to find the composition of the catalyst, but the only
>> description
>> given on internet (found the provider/manufacturer of SOFNOCAT easily by
>> Google) is a precious metal material, and nothing else. Suppose it is
>> impossible to get more info on the composition for manufaiurers reasons.
>>
>> There are two ways to convert CO into CO2:
>> 2CO + O2 = 2CO2 [1]
>> 2CO = CO2 + C [2]
>>
>> Since no oxygen is part of the catalyst material, as I understood,
>> conversion of CO into CO2 only can occur by reaction [2], meaning a
>> carbon
>> stays behind at the surface of the catalyst for each molecule of CO2
>> formed.
>> This also can be an explanation for becoming less effective in time -
>> there
>> is simply less surface of catalyst at which the reaction is taking
>> place.
>> Restoring, eventually can be done by oxydising gently the carbon on the
>> catalysts surface, if not leading to oxidation of the catalyst itself or
>> sintering of the catalyst grains and thus reducing the catalytic surface
>> where the reaction can take place. And sintering may be another
>> reason of
>> decrease in catalyst active surface during the conversion process, if
>> occuring at the applied temperature at all. Further, I am wondering if
>> traces of halogens in your sample gas might effect (pollute) the
>> catalyst,
>> but that is just a suggestion and probably, if happening at all, just a
>> minor effect compared by the first.
>>
>> Another point for this conversion [2] is to consider the effect on the
>> C-isotopic composition? Ideally all oxygen is recovered but C is lost
>> and
>> certainly will introduce isotopic fractionation (how large depends on
>> the
>> conversion temperature; you did not mention that, but I guess a
>> couple of
>> hundred degrees). So, if only oxygen is your interest it will not
>> introduce
>> fractionation, but if also the carbon is of interest you will have a
>> problem.
>>
>> Hope this helps,
>> Best wishes,
>> Pier.
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